-\input texinfo @c -*- texinfo -*-
-@c %**start of header
-@setfilename pspp.info
-@settitle PSPP
-@set TIMESTAMP Time-stamp: Sat Dec 20 20:25:33 WST 2003 jmd
-@set EDITION 0.2
-@set VERSION 0.3
-@c For double-sided printing, uncomment:
-@c @setchapternewpage odd
-@c %**end of header
-
-@macro cmd{CMDNAME}
-\CMDNAME\
-@end macro
-
-@iftex
-@finalout
-@end iftex
-
-@dircategory Math
-@direntry
-* PSPP: (pspp). Statistical analysis package.
-@end direntry
-
-@ifinfo
-PSPP, for statistical analysis of sampled data, by Ben Pfaff.
-
-This file documents PSPP, a statistical package for analysis of
-sampled data that uses a command language compatible with SPSS.
-
-Copyright (C) 1996-9, 2000 Free Software Foundation, Inc.
-
-This version of the PSPP documentation is consistent with version 2 of
-``texinfo.tex''.
-
-Permission is granted to make and distribute verbatim copies of this
-manual provided the copyright notice and this permission notice are
-preserved on all copies.
-
-@ignore
-Permission is granted to process this file through TeX and print the
-results, provided the printed document carries copying permission notice
-identical to this one except for the removal of this paragraph (this
-paragraph not being relevant to the printed manual).
-
-@end ignore
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, provided that the
-entire resulting derived work is distributed under the terms of a
-permission notice identical to this one.
-
-Permission is granted to copy and distribute translations of this
-manual into another language, under the above condition for modified
-versions, except that this permission notice may be stated in a
-translation approved by the Free Software Foundation.
-@end ifinfo
-
-@titlepage
-@title PSPP
-@subtitle A System for Statistical Analysis
-@subtitle Edition @value{EDITION}, for PSPP version @value{VERSION}
-@author by Ben Pfaff
-
-@page
-@vskip 0pt plus 1filll
-
-PSPP Copyright @copyright{} 1997, 1998 Free Software Foundation, Inc.
-
-Permission is granted to make and distribute verbatim copies of this
-manual provided the copyright notice and this permission notice are
-preserved on all copies.
-
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, provided that the
-entire derived work is distributed under the terms of a permission
-notice identical to this one.
-
-Permission is granted to copy and distribute translations of this manual
-into another language, under the above conditions for modified versions,
-except that this permission notice may be stated in a translation
-approved by the Foundation.
-@end titlepage
-
-@node Top, Introduction, (dir), (dir)
-@ifinfo
-@top PSPP
-
-This file documents the PSPP package for statistical analysis of sampled
-data. This is edition @value{EDITION}, for PSPP version
-@value{VERSION}, last modified at @value{TIMESTAMP}.
-
-@end ifinfo
-
-@menu
-* Introduction:: Description of the package.
-* License:: Your rights and obligations.
-* Credits:: Acknowledgement of authors.
-
-* Installation:: How to compile and install PSPP.
-* Configuration:: Configuring PSPP.
-* Invocation:: Starting and running PSPP.
-
-* Language:: Basics of the PSPP command language.
-* Expressions:: Numeric and string expression syntax.
-
-* Data Input and Output:: Reading data from user files.
-* System and Portable Files:: Dealing with system & portable files.
-* Variable Attributes:: Adjusting and examining variables.
-* Data Manipulation:: Simple operations on data.
-* Data Selection:: Select certain cases for analysis.
-* Conditionals and Looping:: Doing things many times or not at all.
-* Statistics:: Basic statistical procedures.
-* Utilities:: Other commands.
-* Not Implemented:: What's not here yet
-
-* Data File Format:: Format of PSPP system files.
-* Portable File Format:: Format of PSPP portable files.
-* q2c Input Format:: Format of syntax accepted by q2c.
-
-* Bugs:: Known problems; submitting bug reports.
-
-* Function Index:: Index of PSPP functions for expressions.
-* Concept Index:: Index of concepts.
-* Command Index:: Index of PSPP procedures.
-
-@end menu
-
-@node Introduction, License, Top, Top
-@chapter Introduction
-@cindex introduction
-
-@cindex PSPP language
-@cindex language, PSPP
-PSPP is a tool for statistical analysis of sampled data. It reads a
-syntax file and a data file, analyzes the data, and writes the results
-to a listing file or to standard output.
-
-The language accepted by PSPP is similar to those accepted by SPSS
-statistical products. The details of PSPP's language are given
-later in this manual.
-
-@cindex files, PSPP
-@cindex output, PSPP
-@cindex PostScript
-@cindex graphics
-@cindex Ghostscript
-@cindex Free Software Foundation
-PSPP produces output in two forms: tables and charts. Both of these can
-be written in several formats; currently, ASCII, PostScript, and HTML
-are supported. In the future, more drivers, such as PCL and X Window
-System drivers, may be developed. For now, Ghostscript, available from
-the Free Software Foundation, may be used to convert PostScript chart
-output to other formats.
-
-The current version of PSPP, @value{VERSION}, is woefully incomplete in
-terms of its statistical procedure support. PSPP is a work in progress.
-The author hopes to support fully support all features in the products
-that PSPP replaces, eventually. The author welcomes questions,
-comments, donations, and code submissions. @xref{Bugs,,Submitting Bug
-Reports}, for instructions on contacting the author.
-
-@node License, Credits, Introduction, Top
-@chapter Your rights and obligations
-@cindex license
-@cindex your rights and obligations
-@cindex rights, your
-@cindex obligations, your
-
-@cindex Free Software Foundation
-@cindex GNU General Public License
-@cindex General Public License
-@cindex GPL
-@cindex distribution
-@cindex redistribution
-Most of PSPP is distributed under the GNU General Public
-License. The General Public License says, in effect, that you may
-modify and distribute PSPP as you like, as long as you grant the
-same rights to others. It also states that you must provide source code
-when you distribute PSPP, or, if you obtained PSPP
-source code from an anonymous ftp site, give out the name of that site.
-
-The General Public License is given in full in the source distribution
-as file @file{COPYING}. In Debian GNU/Linux, this file is also
-available as file @file{/usr/share/common-licenses/GPL-2}.
-
-To quote the GPL itself:
-
-@quotation
-This program is free software; you can redistribute it and/or modify it
-under the terms of the GNU General Public License as published by the
-Free Software Foundation; either version 2 of the License, or (at your
-option) any later version.
-
-This program is distributed in the hope that it will be useful, but
-WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-General Public License for more details.
-
-You should have received a copy of the GNU General Public License along
-with this program; if not, write to the Free Software Foundation, Inc.,
-59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-@end quotation
-
-@node Credits, Installation, License, Top
-@chapter Credits
-@cindex credits
-@cindex authors
-
-@cindex Pfaff, Ben
-Most of PSPP, as well as this manual,
-was written by Ben Pfaff. @xref{Contacting the Author}, for
-instructions on contacting the author.
-
-@cindex Covington, Michael A.
-@cindex Van Zandt, James
-@cindex @file{ftp.cdrom.com}
-@cindex @file{/pub/algorithms/c/julcal10}
-@cindex @file{julcal.c}
-@cindex @file{julcal.h}
-The PSPP source code incorporates @code{julcal10} originally
-written by Michael A. Covington and translated into C by Jim Van Zandt.
-The original package can be found in directory
-@url{ftp://ftp.cdrom.com/pub/algorithms/c/julcal10}. The entire
-contents of that directory constitute the package. The files actually
-used in PSPP are @code{julcal.c} and @code{julcal.h}.
-
-@node Installation, Configuration, Credits, Top
-@chapter Installing PSPP
-@cindex installation
-@cindex PSPP, installing
-
-@cindex GNU C compiler
-@cindex gcc
-@cindex compiler, recommended
-@cindex compiler, gcc
-PSPP conforms to the GNU Coding Standards. PSPP is written in, and
-requires for proper operation, ANSI/ISO C. You might want to
-additionally note the following points:
-
-@itemize @bullet
-@item
-The compiler and linker must allow for significance of several
-characters in external identifiers. The exact number is unknown but at
-least 31 is recommended.
-
-@item
-The @code{int} type must be 32 bits or wider.
-
-@item
-The recommended compiler is gcc 2.7.2.1 or later, but any ANSI compiler
-will do if it fits the above criteria.
-@end itemize
-
-Many UNIX variants should work out-of-the-box, as PSPP uses GNU
-autoconf to detect differences between environments. Please report any
-problems with compilation of PSPP under UNIX and UNIX-like operating
-systems---portability is a major concern of the author.
-
-The pages below give specific instructions for installing PSPP
-on each type of system mentioned above.
-
-@menu
-* UNIX installation:: Installing on UNIX-like environments.
-@end menu
-
-@node UNIX installation, , Installation, Installation
-@section UNIX installation
-@cindex UNIX, installing PSPP under
-@cindex installation, under UNIX
-@noindent
-To install PSPP under a UNIX-like operating system, follow the steps
-below in order. Some of the text below was taken directly from various
-Free Software Foundation sources.
-
-@enumerate
-@item
-@code{cd} to the directory containing the PSPP source.
-
-@cindex configure, GNU
-@cindex GNU configure
-@item
-Type @samp{./configure} to configure for your particular operating
-system and compiler. Running @code{configure} takes a while. While
-running, it displays some messages telling which features it is checking
-for.
-
-You can optionally supply some options to @code{configure} to
-give it hints about how to do its job. Type @code{./configure --help}
-to see a list of options. One of the most useful options is
-@samp{--with-checker}, which enables the use of the Checker memory
-debugger under supported operating systems. Checker must already be
-installed to use this option. Do not use @samp{--with-checker} if you
-are not debugging PSPP itself.
-
-@cindex @file{Makefile}
-@cindex @file{config.h}
-@cindex @file{pref.h}
-@cindex makefile
-@item
-(optional) Edit @file{Makefile}, @file{config.h}, and @file{pref.h}.
-These files are produced by @code{configure}. Note that most PSPP
-settings can be changed at runtime.
-
-@file{pref.h} is only generated by @code{configure} if it does not
-already exist. (It's copied from @file{prefh.orig}.)
-
-@cindex compiling
-@item
-Type @samp{make} to compile the package. If there are any errors during
-compilation, try to fix them. If modifications are necessary to compile
-correctly under your configuration, contact the author.
-@xref{Bugs,,Submitting Bug Reports}, for details.
-
-@cindex self-tests, running
-@item
-Type @samp{make check} to run self-tests on the compiled PSPP package.
-
-@cindex installation
-@cindex PSPP, installing
-@cindex @file{/usr/local/share/pspp/}
-@cindex @file{/usr/local/bin/}
-@cindex @file{/usr/local/info/}
-@cindex documentation, installing
-@item
-Become the superuser and type @samp{make install} to install the
-PSPP binaries, by default in @file{/usr/local/bin/}. The
-directory @file{/usr/local/share/pspp/} is created and populated with
-files needed by PSPP at runtime. This step will also cause the
-PSPP documentation to be installed in @file{/usr/local/info/},
-but only if that directory already exists.
-
-@item
-(optional) Type @samp{make clean} to delete the PSPP binaries
-from the source tree.
-@end enumerate
-
-@node Configuration, Invocation, Installation, Top
-@chapter Configuring PSPP
-@cindex configuration
-@cindex PSPP, configuring
-
-PSPP has dozens of configuration possibilities and hundreds of
-settings. This is both a bane and a blessing. On one hand, it's
-possible to easily accommodate diverse ranges of setups. But, on the
-other, the multitude of possibilities can overwhelm the casual user.
-Fortunately, the configuration mechanisms are profusely described in the
-sections below@enddots{}
-
-@menu
-* File locations:: How PSPP finds config files.
-* Configuration techniques:: Many different methods of configuration@enddots{}
-* Configuration files:: How configuration files are read.
-* Environment variables:: All about environment variables.
-* Output devices:: Describing your terminal(s) and printer(s).
-* PostScript driver class:: Configuration of PostScript devices.
-* ASCII driver class:: Configuration of character-code devices.
-* HTML driver class:: Configuration for HTML output.
-* Miscellaneous configuring:: Even more configuration variables.
-* Improving output quality:: Hints for producing ever-more-lovely output.
-@end menu
-
-@node File locations, Configuration techniques, Configuration, Configuration
-@section Locating configuration files
-
-PSPP uses the same method to find most of its configuration files:
-
-@enumerate
-@item
-The @dfn{base name} of the file being sought is determined.
-
-@item
-The path to search is determined.
-
-@item
-Each directory in the search path, from left to right, is searched for a
-file with the name of the base name. The first occurrence is read
-as the configuration file.
-@end enumerate
-
-The first two steps are elaborated below for the sake of our pedantic
-friends.
-
-@enumerate
-@item
-A @dfn{base name} is a file name lacking an absolute directory
-reference. Some examples of base names are: @file{ps-encodings},
-@file{devices}, @file{devps/DESC} (under UNIX), @file{devps\DESC} (under
-M$ environments).
-
-Determining the base name is a two-step process:
-
-@enumerate a
-@item
-If the appropriate environment variable is defined, the value of that
-variable is used (@pxref{Environment variables}). For instance, when
-searching for the output driver initialization file, the variable
-examined is @code{STAT_OUTPUT_INIT_FILE}.
-
-@item
-Otherwise, the compiled-in default is used. For example, when searching
-for the output driver initialization file, the default base name is
-@file{devices}.
-@end enumerate
-
-@strong{Please note:} If a user-specified base name does contain an
-absolute directory reference, as in a file name like
-@file{/home/pfaff/fonts/TR}, no path is searched---the file name is used
-exactly as given---and the algorithm terminates.
-
-@item
-The path is the first of the following that is defined:
-
-@itemize @bullet
-@item
-A variable definition for the path given in the user environment. This
-is a PSPP-specific environment variable name; for instance,
-@code{STAT_OUTPUT_INIT_PATH}.
-
-@item
-In some cases, another, less-specific environment variable is checked.
-For instance, when searching for font files, the PostScript driver first
-checks for a variable with name @code{STAT_GROFF_FONT_PATH}, then for
-one with name @code{GROFF_FONT_PATH}. (However, font searching has its
-own list of esoteric search rules.)
-
-@item
-The configuration file path, which is itself determined by the
-following rules:
-
-@enumerate a
-@item
-If the command line contains an option of the form @samp{-B @var{path}}
-or @samp{--config-dir=@var{path}}, then the value given on the
-rightmost occurrence of such an option is used.
-
-@item
-Otherwise, if the environment variable @code{STAT_CONFIG_PATH} is
-defined, the value of that variable is used.
-
-@item
-Otherwise, the compiled-in fallback default is used. On UNIX machines,
-the default fallback path is
-
-@enumerate 1
-@item
-@file{~/.pspp}
-
-@item
-@file{/usr/local/lib/pspp}
-
-@item
-@file{/usr/lib/pspp}
-@end enumerate
-
-On DOS machines, the default fallback path is:
-
-@enumerate 1
-@item
-All the paths from the DOS search path in the @samp{PATH} environment
-variable, in left-to-right order.
-
-@item
-@file{C:\PSPP}, as a last resort.
-@end enumerate
-
-Note that the installer of PSPP can easily change this default
-fallback path; thus the above should not be taken as gospel.
-@end enumerate
-@end itemize
-@end enumerate
-
-As a final note: Under DOS, directories given in paths are delimited by
-semicolons (@samp{;}); under UNIX, directories are delimited by colons
-(@samp{:}). This corresponds with the standard path delimiter under
-these OSes.
-
-@node Configuration techniques, Configuration files, File locations, Configuration
-@section Configuration techniques
-
-There are many ways that PSPP can be configured. These are
-described in the list below. Values given by earlier items take
-precedence over those given by later items.
-
-@enumerate
-@item
-Syntax commands that modify settings, such as @cmd{SET}. @xref{SET}.
-
-@item
-Command-line options. @xref{Invocation}.
-
-@item
-PSPP-specific environment variable contents. @xref{Environment
-variables}.
-
-@item
-General environment variable contents. @xref{Environment variables}.
-
-@item
-Configuration file contents. @xref{Configuration files}.
-
-@item
-Fallback defaults.
-@end enumerate
-
-Some of the above may not apply to a particular setting. For instance,
-the current pager (such as @samp{more}, @samp{most}, or @samp{less})
-cannot be determined by configuration file contents because there is no
-appropriate configuration file.
-
-@node Configuration files, Environment variables, Configuration techniques, Configuration
-@section Configuration files
-
-Most configuration files have a common form:
-
-@itemize @bullet
-@item
-Each line forms a separate command or directive. This means that lines
-cannot be broken up, unless they are spliced together with a trailing
-backslash, as described below.
-
-@item
-Before anything else is done, trailing whitespace is removed.
-
-@item
-When a line ends in a backslash (@samp{\}), the backslash is removed,
-and the next line is read and appended to the current line.
-
-@itemize @minus
-@item
-Whitespace preceding the backslash is retained.
-
-@item
-This rule continues to be applied until the line read does not end in a
-backslash.
-
-@item
-It is an error if the last line in the file ends in a backslash.
-@end itemize
-
-@item
-Comments are introduced by an octothorpe (@samp{#}), and continue until the
-end of the line.
-
-@itemize @minus
-@item
-An octothorpe inside balanced pairs of double quotation marks (@samp{"})
-or single quotation marks (@samp{'}) does not introduce a comment.
-
-@item
-The backslash character can be used inside balanced quotes of either
-type to escape the following character as a literal character.
-
-(This is distinct from the use of a backslash as a line-splicing
-character.)
-
-@item
-Line splicing takes place before comment removal.
-@end itemize
-
-@item
-Blank lines, and lines that contain only whitespace, are ignored.
-@end itemize
-
-@node Environment variables, Output devices, Configuration files, Configuration
-@section Environment variables
-
-You may think the concept of environment variables is a fairly simple
-one. However, the author of PSPP has found a way to complicate
-even something so simple. Environment variables are further described
-in the sections below:
-
-@menu
-* Variable values:: Values of variables are determined this way.
-* Environment substitutions:: How environment substitutions are made.
-* Predefined variables:: A few variables are automatically defined.
-@end menu
-
-@node Variable values, Environment substitutions, Environment variables, Environment variables
-@subsection Values of environment variables
-
-Values for environment variables are obtained by the following means,
-which are arranged in order of decreasing precedence:
-
-@enumerate
-@item
-Command-line options. @xref{Invocation}.
-
-@item
-The @file{environment} configuration file---more on this below.
-
-@item
-Actual environment variables (defined in the shell or other parent
-process).
-@end enumerate
-
-The @file{environment} configuration file is located through application
-of the usual algorithm for configuration files (@pxref{File locations}),
-except that its contents do not affect the search path used to find
-@file{environment} itself. Use of @file{environment} is discouraged on
-systems that allow an arbitrarily large environment; it is supported for
-use on systems like MS-DOS that limit environment size.
-
-@file{environment} is composed of lines having the form
-@samp{@var{key}=@var{value}}, where @var{key} and the equals sign
-(@samp{=}) are required, and @var{value} is optional. If @var{value} is
-given, variable @var{key} is given that value; if @var{value} is absent,
-variable @var{key} is undefined (deleted). Variables may not be defined
-with a null value.
-
-Environment substitutions are performed on each line in the file
-(@pxref{Environment substitutions}).
-
-See @ref{Configuration files}, for more details on formatting of the
-environment configuration file.
-
-@quotation
-@strong{Please note:} Support for @file{environment} is not yet
-implemented.
-@end quotation
-
-@node Environment substitutions, Predefined variables, Variable values, Environment variables
-@subsection Environment substitutions
-
-Much of the power of environment variables lies in the way that they may
-be substituted into configuration files. Variable substitutions are
-described below.
-
-The line is scanned from left to right. In this scan, all characters
-other than dollar signs (@samp{$}) are retained unmolested. Dollar
-signs, however, introduce an environment variable reference. References
-take three forms:
-
-@table @code
-@item $@var{var}
-Replaced by the value of environment variable @var{var}, determined as
-specified in @ref{Variable values}. @var{var} must be one of the
-following:
-
-@itemize @bullet
-@item
-One or more letters.
-
-@item
-Exactly one nonalphabetic character. This may not be a left brace
-(@samp{@{}).
-@end itemize
-
-@item $@{@var{var}@}
-Same as above, but @var{var} may contain any character (except
-@samp{@}}).
-
-@item $$
-Replaced by a single dollar sign.
-@end table
-
-Undefined variables expand to a empty value.
-
-@node Predefined variables, , Environment substitutions, Environment variables
-@subsection Predefined environment variables
-
-There are two environment variables predefined for use in environment
-substitutions:
-
-@table @samp
-@item VER
-Defined as the version number of PSPP, as a string, in a format
-something like @samp{0.9.4}.
-
-@item ARCH
-Defined as the host architecture of PSPP, as a string, in standard
-cpu-manufacturer-OS format. For instance, Debian GNU/Linux 1.1 on an
-Intel machine defines this as @samp{i586-unknown-linux}. This is
-somewhat dependent on the system used to compile PSPP.
-@end table
-
-Nothing prevents these values from being overridden, although it's a
-good idea not to do so.
-
-@node Output devices, PostScript driver class, Environment variables, Configuration
-@section Output devices
-
-Configuring output devices is the most complicated aspect of configuring
-PSPP. The output device configuration file is named
-@file{devices}. It is searched for using the usual algorithm for
-finding configuration files (@pxref{File locations}). Each line in the
-file is read in the usual manner for configuration files
-(@pxref{Configuration files}).
-
-Lines in @file{devices} are divided into three categories, described
-briefly in the table below:
-
-@table @i
-@item driver category definitions
-Define a driver in terms of other drivers.
-
-@item macro definitions
-Define environment variables local to the the output driver
-configuration file.
-
-@item device definitions
-Describe the configuration of an output device.
-@end table
-
-The following sections further elaborate the contents of the
-@file{devices} file.
-
-@menu
-* Driver categories:: How to organize the driver namespace.
-* Macro definitions:: Environment variables local to @file{devices}.
-* Device definitions:: Output device descriptions.
-* Dimensions:: Lengths, widths, sizes, @enddots{}
-* papersize:: Letter, legal, A4, envelope, @enddots{}
-* Distinguishing line types:: Details on @file{devices} parsing.
-* Tokenizing lines:: Dividing @file{devices} lines into tokens.
-@end menu
-
-@node Driver categories, Macro definitions, Output devices, Output devices
-@subsection Driver categories
-
-Drivers can be divided into categories. Drivers are specified by their
-names, or by the names of the categories that they are contained in.
-Only certain drivers are enabled each time PSPP is run; by
-default, these are the drivers in the category `default'. To enable a
-different set of drivers, use the @samp{-o @var{device}} command-line
-option (@pxref{Invocation}).
-
-Categories are specified with a line of the form
-@samp{@var{category}=@var{driver1} @var{driver2} @var{driver3} @var{@dots{}}
-@var{driver@var{n}}}. This line specifies that the category
-@var{category} is composed of drivers named @var{driver1},
-@var{driver2}, and so on. There may be any number of drivers in the
-category, from zero on up.
-
-Categories may also be specified on the command line
-(@pxref{Invocation}).
-
-This is all you need to know about categories. If you're still curious,
-read on.
-
-First of all, the term `categories' is a bit of a misnomer. In fact,
-the internal representation is nothing like the hierarchy that the term
-seems to imply: a linear list is used to keep track of the enabled
-drivers.
-
-When PSPP first begins reading @file{devices}, this list contains
-the name of any drivers or categories specified on the command line, or
-the single item `default' if none were specified.
-
-Each time a category definition is specified, the list is searched for
-an item with the value of @var{category}. If a matching item is found,
-it is deleted. If there was a match, the list of drivers (@var{driver1}
-through @var{driver@var{n}}) is then appended to the list.
-
-Each time a driver definition line is encountered, the list is searched.
-If the list contains an item with that driver's name, the driver is
-enabled and the item is deleted from the list. Otherwise, the driver
-is not enabled.
-
-It is an error if the list is not empty when the end of @file{devices}
-is reached.
-
-@node Macro definitions, Device definitions, Driver categories, Output devices
-@subsection Macro definitions
-
-Macro definitions take the form @samp{define @var{macroname}
-@var{definition}}. In such a macro definition, the environment variable
-@var{macroname} is defined to expand to the value @var{definition}.
-Before the definition is made, however, any macros used in
-@var{definition} are expanded.
-
-Please note the following nuances of macro usage:
-
-@itemize @bullet
-@item
-For the purposes of this section, @dfn{macro} and @dfn{environment
-variable} are synonyms.
-
-@item
-Macros may not take arguments.
-
-@item
-Macros may not recurse.
-
-@item
-Macros are just environment variable definitions like other environment
-variable definitions, with the exception that they are limited in scope
-to the @file{devices} configuration file.
-
-@item
-Macros override other all environment variables of the same name (within
-the scope of @file{devices}).
-
-@item
-Earlier macro definitions for a particular @var{key} override later
-ones. In particular, macro definitions on the command line override
-those in the device definition file. @xref{Non-option Arguments}.
-
-@item
-There are two predefined macros, whose values are determined at runtime:
-
-@table @samp
-@item viewwidth
-Defined as the width of the console screen, in columns of text.
-
-@item viewlength
-Defined as the length of the console screen, in lines of text.
-@end table
-@end itemize
-
-@node Device definitions, Dimensions, Macro definitions, Output devices
-@subsection Driver definitions
-
-Driver definitions are the ultimate purpose of the @file{devices}
-configuration file. These are where the real action is. Driver
-definitions tell PSPP where it should send its output.
-
-Each driver definition line is divided into four fields. These fields
-are delimited by colons (@samp{:}). Each line is subjected to
-environment variable interpolation before it is processed further
-(@pxref{Environment substitutions}). From left to right, the four
-fields are, in brief:
-
-@table @i
-@item driver name
-A unique identifier, used to determine whether to enable the driver.
-
-@item class name
-One of the predefined driver classes supported by PSPP. The
-currently supported driver classes include `postscript' and `ascii'.
-
-@item device type(s)
-Zero or more of the following keywords, delimited by spaces:
-
-@table @code
-@item screen
-
-Indicates that the device is a screen display. This may reduce the
-amount of buffering done by the driver, to make interactive use more
-convenient.
-
-@item printer
-
-Indicates that the device is a printer.
-
-@item listing
-
-Indicates that the device is a listing file.
-@end table
-
-These options are just hints to PSPP and do not cause the output to be
-directed to the screen, or to the printer, or to a listing file---those
-must be set elsewhere in the options. They are used primarily to decide
-which devices should be enabled at any given time. @xref{SET}, for more
-information.
-
-@item options
-An optional set of options to pass to the driver itself. The exact
-format for the options varies among drivers.
-@end table
-
-The driver is enabled if:
-
-@enumerate
-@item
-Its driver name is specified on the command line, or
-
-@item
-It's in a category specified on the command line, or
-
-@item
-If no categories or driver names are specified on the command line, it
-is in category @code{default}.
-@end enumerate
-
-For more information on driver names, see @ref{Driver categories}.
-
-The class name must be one of those supported by PSPP. The
-classes supported depend on the options with which PSPP was
-compiled. See later sections in this chapter for descriptions of the
-available driver classes.
-
-Options are dependent on the driver. See the driver descriptions for
-details.
-
-@node Dimensions, papersize, Device definitions, Output devices
-@subsection Dimensions
-
-Quite often in configuration it is necessary to specify a length or a
-size. PSPP uses a common syntax for all such, calling them
-collectively by the name @dfn{dimensions}.
-
-@itemize @bullet
-@item
-You can specify dimensions in decimal form (@samp{12.5}) or as
-fractions, either as mixed numbers (@samp{12-1/2}) or raw fractions
-(@samp{25/2}).
-
-@item
-A number of different units are available. These are suffixed to the
-numeric part of the dimension. There must be no spaces between the
-number and the unit. The available units are identical to those offered
-by the popular typesetting system @TeX{}:
-
-@table @code
-@item in
-inch (1 @code{in} = 2.54 @code{cm})
-
-@item "
-inch (1 @code{in} = 2.54 @code{cm})
-
-@item pt
-printer's point (1 @code{in} = 72.27 @code{pt})
-
-@item pc
-pica (12 @code{pt} = 1 @code{pc})
-
-@item bp
-PostScript point (1 @code{in} = 72 @code{bp})
-
-@item cm
-centimeter
-
-@item mm
-millimeter (10 @code{mm} = 1 @code{cm})
-
-@item dd
-didot point (1157 @code{dd} = 1238 @code{pt})
-
-@item cc
-cicero (1 @code{cc} = 12 @code{dd})
-
-@item sp
-scaled point (65536 @code{sp} = 1 @code{pt})
-@end table
-
-@item
-If no explicit unit is given, PSPP attempts to guess the best unit:
-
-@itemize @minus
-@item
-Numbers less than 50 are assumed to be in inches.
-
-@item
-Numbers 50 or greater are assumed to be in millimeters.
-@end itemize
-@end itemize
-
-@node papersize, Distinguishing line types, Dimensions, Output devices
-@subsection Paper sizes
-
-Output drivers usually deal with some sort of hardcopy media. This
-media is called @dfn{paper} by the drivers, though in reality it could
-be a transparency or film or thinly veiled sarcasm. To make it easier
-for you to deal with paper, PSPP allows you to have (of course!) a
-configuration file that gives symbolic names, like ``letter'' or
-``legal'' or ``a4'', to paper sizes, rather than forcing you to use
-cryptic numbers like ``8-1/2 x 11'' or ``210 by 297''. Surprisingly
-enough, this configuration file is named @file{papersize}.
-@xref{Configuration files}.
-
-When PSPP tries to connect a symbolic paper name to a paper size, it
-reads and parses each non-comment line in the file, in order. The first
-field on each line must be a symbolic paper name in double quotes.
-Paper names may not contain double quotes. Paper names are not
-case-sensitive: @samp{legal} and @samp{Legal} are equivalent.
-
-If a match is found for the paper name, the rest of the line is parsed.
-If it is found to be a pair of dimensions (@pxref{Dimensions}) separated
-by either @samp{x} or @samp{by}, then those are taken to be the paper
-size, in order of width followed by length. There @emph{must} be at
-least one space on each side of @samp{x} or @samp{by}.
-
-Otherwise the line must be of the form
-@samp{"@var{paper-1}"="@var{paper-2}"}. In this case the target of the
-search becomes paper name @var{paper-2} and the search through the file
-continues.
-
-@node Distinguishing line types, Tokenizing lines, papersize, Output devices
-@subsection How lines are divided into types
-
-The lines in @file{devices} are distinguished in the following manner:
-
-@enumerate
-@item
-Leading whitespace is removed.
-
-@item
-If the resulting line begins with the exact string @code{define},
-followed by one or more whitespace characters, the line is processed as
-a macro definition.
-
-@item
-Otherwise, the line is scanned for the first instance of a colon
-(@samp{:}) or an equals sign (@samp{=}).
-
-@item
-If a colon is encountered first, the line is processed as a driver
-definition.
-
-@item
-Otherwise, if an equals sign is encountered, the line is processed as a
-macro definition.
-
-@item
-Otherwise, the line is ill-formed.
-@end enumerate
-
-@node Tokenizing lines, , Distinguishing line types, Output devices
-@subsection How lines are divided into tokens
-
-Each driver definition line is run through a simple tokenizer. This
-tokenizer recognizes two basic types of tokens.
-
-The first type is an equals sign (@samp{=}). Equals signs are both
-delimiters between tokens and tokens in themselves.
-
-The second type is an identifier or string token. Identifiers and
-strings are equivalent after tokenization, though they are written
-differently. An identifier is any string of characters other than
-whitespace or equals sign.
-
-A string is introduced by a single- or double-quote character (@samp{'}
-or @samp{"}) and, in general, continues until the next occurrence of
-that same character. The following standard C escapes can also be
-embedded within strings:
-
-@table @code
-@item \'
-A single-quote (@samp{'}).
-
-@item \"
-A double-quote (@samp{"}).
-
-@item \?
-A question mark (@samp{?}). Included for hysterical raisins.
-
-@item \\
-A backslash (@samp{\}).
-
-@item \a
-Audio bell (ASCII 7).
-
-@item \b
-Backspace (ASCII 8).
-
-@item \f
-Formfeed (ASCII 12).
-
-@item \n
-New-line (ASCII 10)
-
-@item \r
-Carriage return (ASCII 13).
-
-@item \t
-Tab (ASCII 9).
-
-@item \v
-Vertical tab (ASCII 11).
-
-@item \@var{o}@var{o}@var{o}
-Each @samp{o} must be an octal digit. The character is the one having
-the octal value specified. Any number of octal digits is read and
-interpreted; only the lower 8 bits are used.
-
-@item \x@var{h}@var{h}
-Each @samp{h} must be a hex digit. The character is the one having the
-hexadecimal value specified. Any number of hex digits is read and
-interpreted; only the lower 8 bits are used.
-@end table
-
-Tokens, outside of quoted strings, are delimited by whitespace or equals
-signs.
-
-@node PostScript driver class, ASCII driver class, Output devices, Configuration
-@section The PostScript driver class
-
-The @code{postscript} driver class is used to produce output that is
-acceptable to PostScript printers and to PC-based PostScript
-interpreters such as Ghostscript. Continuing a long tradition,
-PSPP's PostScript driver is configurable to the point of
-absurdity.
-
-There are actually two PostScript drivers. The first one,
-@samp{postscript}, produces ordinary DSC-compliant PostScript output.
-The second one @samp{epsf}, produces an Encapsulated PostScript file.
-The two drivers are otherwise identical in configuration and in
-operation.
-
-The PostScript driver is described in further detail below.
-
-@menu
-* PS output options:: Output file options.
-* PS page options:: Paper, margins, scaling & rotation, more!
-* PS file options:: Configuration files.
-* PS font options:: Default fonts, font options.
-* PS line options:: Line widths, options.
-* Prologue:: Details on the PostScript prologue.
-* Encodings:: Details on PostScript font encodings.
-@end menu
-
-@node PS output options, PS page options, PostScript driver class, PostScript driver class
-@subsection PostScript output options
-
-These options deal with the form of the output and the output file
-itself:
-
-@table @code
-@item output-file=@var{filename}
-
-File to which output should be sent. This can be an ordinary filename
-(i.e., @code{"pspp.ps"}), a pipe filename (i.e., @code{"|lpr"}), or
-stdout (@code{"-"}). Default: @code{"pspp.ps"}.
-
-@item color=@var{boolean}
-
-Most of the time black-and-white PostScript devices are smart enough to
-map colors to shades themselves. However, you can cause the PSPP
-output driver to do an ugly simulation of this in its own driver by
-turning @code{color} off. Default: @code{on}.
-
-This is a boolean setting, as are many settings in the PostScript
-driver. Valid positive boolean values are @samp{on}, @samp{true},
-@samp{yes}, and nonzero integers. Negative boolean values are
-@samp{off}, @samp{false}, @samp{no}, and zero.
-
-@item data=@var{data-type}
-
-One of @code{clean7bit}, @code{clean8bit}, or @code{binary}. This
-controls what characters will be written to the output file. PostScript
-produced with @code{clean7bit} can be transmitted over 7-bit
-transmission channels that use ASCII control characters for line
-control. @code{clean8bit} is similar but allows characters above 127 to
-be written to the output file. @code{binary} allows any character in
-the output file. Default: @code{clean7bit}.
-
-@item line-ends=@var{line-end-type}
-
-One of @code{cr}, @code{lf}, or @code{crlf}. This controls what is used
-for new-line in the output file. Default: @code{cr}.
-
-@item optimize-line-size=@var{level}
-
-Either @code{0} or @code{1}. If @var{level} is @code{1}, then short
-line segments will be collected and merged into longer ones. This
-reduces output file size but requires more time and memory. A
-@var{level} of @code{0} has the advantage of being better for
-interactive environments. @code{1} is the default unless the
-@code{screen} flag is set; in that case, the default is @code{0}.
-
-@item optimize-text-size=@var{level}
-
-One of @code{0}, @code{1}, or @code{2}, each higher level representing
-correspondingly more aggressive space savings for text in the output
-file and requiring correspondingly more time and memory. Unfortunately
-the levels presently are all the same. @code{1} is the default unless
-the @code{screen} flag is set; in that case, the default is @code{0}.
-@end table
-
-@node PS page options, PS file options, PS output options, PostScript driver class
-@subsection PostScript page options
-
-These options affect page setup:
-
-@table @code
-@item headers=@var{boolean}
-
-Controls whether the standard headers showing the time and date and
-title and subtitle are printed at the top of each page. Default:
-@code{on}.
-
-@item paper-size=@var{paper-size}
-
-Paper size, either as a symbolic name (i.e., @code{letter} or @code{a4})
-or specific measurements (i.e., @code{8-1/2x11} or @code{"210 x 297"}.
-@xref{papersize, , Paper sizes}. Default: @code{letter}.
-
-@item orientation=@var{orientation}
-
-Either @code{portrait} or @code{landscape}. Default: @code{portrait}.
-
-@item left-margin=@var{dimension}
-@itemx right-margin=@var{dimension}
-@itemx top-margin=@var{dimension}
-@itemx bottom-margin=@var{dimension}
-
-Sets the margins around the page. The headers, if enabled, are not
-included in the margins; they are in addition to the margins. For a
-description of dimensions, see @ref{Dimensions}. Default: @code{0.5in}.
-
-@end table
-
-@node PS file options, PS font options, PS page options, PostScript driver class
-@subsection PostScript file options
-
-Oh, my. You don't really want to know about the way that the PostScript
-driver deals with files, do you? Well I suppose you're entitled, but I
-warn you right now: it's not pretty. Here goes@enddots{}
-
-First let's look at the options that are available:
-
-@table @code
-
-@item font-dir=@var{font-directory}
-
-Sets the font directory. Default: @code{devps}.
-
-@item prologue-file=@var{prologue-file-name}
-
-Sets the name of the PostScript prologue file. You can write your own
-prologue, though I have no idea why you'd want to: see @ref{Prologue}.
-Default: @code{ps-prologue}.
-
-@item device-file=@var{device-file-name}
-
-Sets the name of the Groff-format device description file. The
-PostScript driver reads this to know about the scaling of fonts
-and so on. The format of such files is described in groff_font(5),
-included with Groff. Default: @code{DESC}.
-
-@item encoding-file=@var{encoding-file-name}
-
-Sets the name of the encoding file. This file contains a list of all
-font encodings that will be needed so that the driver can put all of
-them at the top of the prologue. @xref{Encodings}. Default:
-@code{ps-encodings}.
-
-If the specified encoding file cannot be found, this error will be
-silently ignored, since most people do not need any encodings besides
-the ones that can be found using @code{auto-encodings}, described below.
-
-@item auto-encode=@var{boolean}
-
-When enabled, the font encodings needed by the default proportional- and
-fixed-pitch fonts will automatically be dumped to the PostScript
-output. Otherwise, it is assumed that the user has an encoding file
-and knows how to use it (@pxref{Encodings}). There is probably no good
-reason to turn off this convenient feature. Default: @code{on}.
-
-@end table
-
-Next I suppose it's time to describe the search algorithm. When the
-PostScript driver needs a file, whether that file be a font, a
-PostScript prologue, or what you will, it searches in this manner:
-
-@enumerate
-
-@item
-Constructs a path by taking the first of the following that is defined:
-
-@enumerate a
-
-@item
-Environment variable @code{STAT_GROFF_FONT_PATH}. @xref{Environment
-variables}.
-
-@item
-Environment variable @code{GROFF_FONT_PATH}.
-
-@item
-The compiled-in fallback default.
-@end enumerate
-
-@item
-Constructs a base name from concatenating, in order, the font directory,
-a path separator (@samp{/} or @samp{\}), and the file to be found. A
-typical base name would be something like @code{devps/ps-encodings}.
-
-@item
-Searches for the base name in the path constructed above. If the file
-is found, the algorithm terminates.
-
-@item
-Searches for the base name in the standard configuration path. See
-@ref{File locations}, for more details. If the file is found, the
-algorithm terminates.
-
-@item
-At this point we remove the font directory and path separator from the
-base name. Now the base name is simply the file to be found, i.e.,
-@code{ps-encodings}.
-
-@item
-Searches for the base name in the path constructed in the first step.
-If the file is found, the algorithm terminates.
-
-@item
-Searches for the base name in the standard configuration path. If the
-file is found, the algorithm terminates.
-
-@item
-The algorithm terminates unsuccessfully.
-@end enumerate
-
-So, as you see, there are several ways to configure the PostScript
-drivers. Careful selection of techniques can make the configuration
-very flexible indeed.
-
-@node PS font options, PS line options, PS file options, PostScript driver class
-@subsection PostScript font options
-
-The list of available font options is short and sweet:
-
-@table @code
-@item prop-font=@var{font-name}
-
-Sets the default proportional font. The name should be that of a
-PostScript font. Default: @code{"Helvetica"}.
-
-@item fixed-font=@var{font-name}
-
-Sets the default fixed-pitch font. The name should be that of a
-PostScript font. Default: @code{"Courier"}.
-
-@item font-size=@var{font-size}
-
-Sets the size of the default fonts, in thousandths of a point. Default:
-@code{10000}.
-
-@end table
-
-@node PS line options, Prologue, PS font options, PostScript driver class
-@subsection PostScript line options
-
-Most tables contain lines, or rules, between cells. Some features of
-the way that lines are drawn in PostScript tables are user-definable:
-
-@table @code
-
-@item line-style=@var{style}
-
-Sets the style used for lines used to divide tables into sections.
-@var{style} must be either @code{thick}, in which case thick lines are
-used, or @var{double}, in which case double lines are used. Default:
-@code{thick}.
-
-@item line-gutter=@var{dimension}
-
-Sets the line gutter, which is the amount of whitespace on either side
-of lines that border text or graphics objects. @xref{Dimensions}.
-Default: @code{0.5pt}.
-
-@item line-spacing=@var{dimension}
-
-Sets the line spacing, which is the amount of whitespace that separates
-lines that are side by side, as in a double line. Default:
-@code{0.5pt}.
-
-@item line-width=@var{dimension}
-
-Sets the width of a typical line used in tables. Default: @code{0.5pt}.
-
-@item line-width-thick=@var{dimension}
-
-Sets the width of a thick line used in tables. Not used if
-@code{line-style} is set to @code{thick}. Default: @code{1.5pt}.
-
-@end table
-
-@node Prologue, Encodings, PS line options, PostScript driver class
-@subsection The PostScript prologue
-
-Most PostScript files that are generated mechanically by programs
-consist of two parts: a prologue and a body. The prologue is generally
-a collection of boilerplate. Only the body differs greatly between
-two outputs from the same program.
-
-This is also the strategy used in the PSPP PostScript driver. In
-general, the prologue supplied with PSPP will be more than sufficient.
-In this case, you will not need to read the rest of this section.
-However, hackers might want to know more. Read on, if you fall into
-this category.
-
-The prologue is dumped into the output stream essentially unmodified.
-However, two actions are performed on its lines. First, certain lines
-may be omitted as specified in the prologue file itself. Second,
-variables are substituted.
-
-The following lines are omitted:
-
-@enumerate
-@item
-All lines that contain three bangs in a row (@code{!!!}).
-
-@item
-Lines that contain @code{!eps}, if the PostScript driver is producing
-ordinary PostScript output. Otherwise an EPS file is being produced,
-and the line is included in the output, although everything following
-@code{!eps} is deleted.
-
-@item
-Lines that contain @code{!ps}, if the PostScript driver is producing EPS
-output. Otherwise, ordinary PostScript is being produced, and the line
-is included in the output, although everything following @code{!ps} is
-deleted.
-@end enumerate
-
-The following are the variables that are substituted. Only the
-variables listed are substituted; environment variables are not.
-@xref{Environment substitutions}.
-
-@table @code
-@item bounding-box
-
-The page bounding box, in points, as four space-separated numbers. For
-U.S. letter size paper, this is @samp{0 0 612 792}.
-
-@item creator
-
-PSPP version as a string: @samp{GNU PSPP 0.1b}, for example.
-
-@item date
-
-Date the file was created. Example: @samp{Tue May 21 13:46:22 1991}.
-
-@item data
-
-Value of the @code{data} PostScript driver option, as one of the strings
-@samp{Clean7Bit}, @samp{Clean8Bit}, or @samp{Binary}.
-
-@item orientation
-
-Page orientation, as one of the strings @code{Portrait} or
-@code{Landscape}.
-
-@item user
-
-Under multiuser OSes, the user's login name, taken either from the
-environment variable @code{LOGNAME} or, if that fails, the result of the
-C library function @code{getlogin()}. Defaults to @samp{nobody}.
-
-@item host
-
-System hostname as reported by @code{gethostname()}. Defaults to
-@samp{nowhere}.
-
-@item prop-font
-
-Name of the default proportional font, prefixed by the word
-@samp{font} and a space. Example: @samp{font Times-Roman}.
-
-@item fixed-font
-
-Name of the default fixed-pitch font, prefixed by the word @samp{font}
-and a space.
-
-@item scale-factor
-
-The page scaling factor as a floating-point number. Example:
-@code{1.0}. Note that this is also passed as an argument to the BP
-macro.
-
-@item paper-length
-@item paper-width
-
-The paper length and paper width, respectively, in thousandths of a
-point. Note that these are also passed as arguments to the BP macro.
-
-@item left-margin
-@item top-margin
-
-The left margin and top margin, respectively, in thousandths of a
-point. Note that these are also passed as arguments to the BP macro.
-
-@item title
-
-Document title as a string. This is not the title specified in the
-PSPP syntax file. A typical title is the word @samp{PSPP} followed
-by the syntax file name in parentheses. Example: @samp{PSPP
-(<stdin>)}.
-
-@item source-file
-
-PSPP syntax file name. Example: @samp{mary96/first.stat}.
-
-@end table
-
-Any other questions about the PostScript prologue can best be answered
-by examining the default prologue or the PSPP source.
-
-@node Encodings, , Prologue, PostScript driver class
-@subsection PostScript encodings
-
-PostScript fonts often contain many more than 256 characters, in order
-to accommodate foreign language characters and special symbols.
-PostScript uses @dfn{encodings} to map these onto single-byte symbol
-sets. Each font can have many different encodings applied to it.
-
-PSPP's PostScript driver needs to know which encoding to apply to each
-font. It can determine this from the information encapsulated in the
-Groff font description that it reads. However, there is an additional
-problem---for efficiency, the PostScript driver needs to have a complete
-list of all encodings that will be used in the entire session @emph{when
-it opens the output file}. For this reason, it can't use the
-information built into the fonts because it doesn't know which fonts
-will be used.
-
-As a stopgap solution, there are two mechanisms for specifying which
-encodings will be used. The first mechanism is automatic and it is the
-only one that most PSPP users will ever need. The second mechanism is
-manual, but it is more flexible. Either mechanism or both may be used
-at one time.
-
-The first mechanism is activated by the @samp{auto-encode} driver option
-(@pxref{PS file options}). When enabled, @samp{auto-encode} causes the
-PostScript driver to include the encodings used by the default
-proportional and fixed-pitch fonts (@pxref{PS font options}). Many
-PSPP output files will only need these encodings.
-
-The second mechanism is the file specified by the @samp{encoding-file}
-option (@pxref{PS file options}). If it exists, this file must consist
-of lines in PSPP configuration-file format (@pxref{Configuration
-files}). Each line that is not a comment should name a PostScript
-encoding to include in the output.
-
-It is not an error if an encoding is included more than once, by either
-mechanism. It will appear only once in the output. It is also not an
-error if an encoding is included in the output but never used. It
-@emph{is} an error if an encoding is used but not included by one of
-these mechanisms. In this case, the built-in PostScript encoding
-@samp{ISOLatin1Encoding} is substituted.
-
-@node ASCII driver class, HTML driver class, PostScript driver class, Configuration
-@section The ASCII driver class
-
-The ASCII driver class produces output that can be displayed on a
-terminal or output to printers. All of its options are highly
-configurable. The ASCII driver has class name @samp{ascii}.
-
-The ASCII driver is described in further detail below.
-
-@menu
-* ASCII output options:: Output file options.
-* ASCII page options:: Page size, margins, more.
-* ASCII font options:: Box character, bold & italics.
-@end menu
-
-@node ASCII output options, ASCII page options, ASCII driver class, ASCII driver class
-@subsection ASCII output options
-
-@table @code
-@item output-file=@var{filename}
-
-File to which output should be sent. This can be an ordinary filename
-(e.g., @code{"pspp.txt"}), a pipe filename (e.g., @code{"|lpr"}), or
-stdout (@code{"-"}). Default: @code{"pspp.list"}.
-
-@item char-set=@var{char-set-type}
-
-One of @samp{ascii} or @samp{latin1}. This has no effect on output at
-the present time. Default: @code{ascii}.
-
-@item form-feed-string=@var{form-feed-value}
-
-The string written to the output to cause a formfeed. See also
-@code{paginate}, described below, for a related setting. Default:
-@code{"\f"}.
-
-@item newline-string=@var{new-line-value}
-
-The string written to the output to cause a new-line (carriage return
-plus linefeed). The default, which can be specified explicitly with
-@code{newline-string=default}, is to use the system-dependent new-line
-sequence by opening the output file in text mode. This is usually the
-right choice.
-
-However, @code{newline-string} can be set to any string. When this is
-done, the output file is opened in binary mode.
-
-@item paginate=@var{boolean}
-
-If set, a formfeed (as set in @code{form-feed-string}, described above)
-will be written to the device after every page. Default: @code{on}.
-
-@item tab-width=@var{tab-width-value}
-
-The distance between tab stops for this device. If set to 0, tabs will
-not be used in the output. Default: @code{8}.
-
-@item init=@var{initialization-string}.
-
-String written to the device before anything else, at the beginning of
-the output. Default: @code{""} (the empty string).
-
-@item done=@var{finalization-string}.
-
-String written to the device after everything else, at the end of the
-output. Default: @code{""} (the empty string).
-@end table
-
-@node ASCII page options, ASCII font options, ASCII output options, ASCII driver class
-@subsection ASCII page options
-
-These options affect page setup:
-
-@table @code
-@item headers=@var{boolean}
-
-If enabled, two lines of header information giving title and subtitle,
-page number, date and time, and PSPP version are printed at the top of
-every page. These two lines are in addition to any top margin
-requested. Default: @code{on}.
-
-@item length=@var{line-count}
-
-Physical length of a page, in lines. Headers and margins are subtracted
-from this value. Default: @code{66}.
-
-@item width=@var{character-count}
-
-Physical width of a page, in characters. Margins are subtracted from
-this value. Default: @code{130}.
-
-@item lpi=@var{lines-per-inch}
-
-Number of lines per vertical inch. Not currently used. Default: @code{6}.
-
-@item cpi=@var{characters-per-inch}
-
-Number of characters per horizontal inch. Not currently used. Default:
-@code{10}.
-
-@item left-margin=@var{left-margin-width}
-
-Width of the left margin, in characters. PSPP subtracts this value
-from the page width. Default: @code{0}.
-
-@item right-margin=@var{right-margin-width}
-
-Width of the right margin, in characters. PSPP subtracts this value
-from the page width. Default: @code{0}.
-
-@item top-margin=@var{top-margin-lines}
-
-Length of the top margin, in lines. PSPP subtracts this value from
-the page length. Default: @code{2}.
-
-@item bottom-margin=@var{bottom-margin-lines}
-
-Length of the bottom margin, in lines. PSPP subtracts this value from
-the page length. Default: @code{2}.
-
-@end table
-
-@node ASCII font options, , ASCII page options, ASCII driver class
-@subsection ASCII font options
-
-These are the ASCII font options:
-
-@table @code
-@item box[@var{line-type}]=@var{box-chars}
-
-The characters used for lines in tables produced by the ASCII driver can
-be changed using this option. @var{line-type} is used to indicate which
-type of line to change; @var{box-chars} is the character or string of
-characters to use for this type of line.
-
-@var{line-type} must be a 4-digit number in base 4. The digits are in
-the order `right', `bottom', `left', `top'. The four possibilities for
-each digit are:
-
-@table @asis
-@item 0
-No line.
-
-@item 1
-Single line.
-
-@item 2
-Double line.
-
-@item 3
-Special device-defined line, if one is available; otherwise, a double
-line.
-@end table
-
-Examples:
-
-@table @code
-@item box[0101]="|"
-
-Sets @samp{|} as the character to use for a single-width line with
-bottom and top components.
-
-@item box[2222]="#"
-
-Sets @samp{#} as the character to use for the intersection of four
-double-width lines, one each from the top, bottom, left and right.
-
-@item box[1100]="\xda"
-
-Sets @samp{"\xda"}, which under MS-DOS is a box character suitable for
-the top-left corner of a box, as the character for the intersection of
-two single-width lines, one each from the right and bottom.
-
-@end table
-
-Defaults:
-
-@itemize @bullet
-@item
-@code{box[0000]=" "}
-
-@item
-@code{box[1000]="-"}
-@*@code{box[0010]="-"}
-@*@code{box[1010]="-"}
-
-@item
-@code{box[0100]="|"}
-@*@code{box[0001]="|"}
-@*@code{box[0101]="|"}
-
-@item
-@code{box[2000]="="}
-@*@code{box[0020]="="}
-@*@code{box[2020]="="}
-
-@item
-@code{box[0200]="#"}
-@*@code{box[0002]="#"}
-@*@code{box[0202]="#"}
-
-@item
-@code{box[3000]="="}
-@*@code{box[0030]="="}
-@*@code{box[3030]="="}
-
-@item
-@code{box[0300]="#"}
-@*@code{box[0003]="#"}
-@*@code{box[0303]="#"}
-
-@item
-For all others, @samp{+} is used unless there are double lines or
-special lines, in which case @samp{#} is used.
-@end itemize
-
-@item italic-on=@var{italic-on-string}
-
-Character sequence written to turn on italics or underline printing. If
-this is set to @code{overstrike}, then the driver will simulate
-underlining by overstriking with underscore characters (@samp{_}) in the
-manner described by @code{overstrike-style} and
-@code{carriage-return-style}. Default: @code{overstrike}.
-
-@item italic-off=@var{italic-off-string}
-
-Character sequence to turn off italics or underline printing. Default:
-@code{""} (the empty string).
-
-@item bold-on=@var{bold-on-string}
-
-Character sequence written to turn on bold or emphasized printing. If
-set to @code{overstrike}, then the driver will simulated bold printing
-by overstriking characters in the manner described by
-@code{overstrike-style} and @code{carriage-return-style}. Default:
-@code{overstrike}.
-
-@item bold-off=@var{bold-off-string}
-
-Character sequence to turn off bold or emphasized printing. Default:
-@code{""} (the empty string).
-
-@item bold-italic-on=@var{bold-italic-on-string}
-
-Character sequence written to turn on bold-italic printing. If set to
-@code{overstrike}, then the driver will simulate bold-italics by
-overstriking twice, once with the character, a second time with an
-underscore (@samp{_}) character, in the manner described by
-@code{overstrike-style} and @code{carriage-return-style}. Default:
-@code{overstrike}.
-
-@item bold-italic-off=@var{bold-italic-off-string}
-
-Character sequence to turn off bold-italic printing. Default: @code{""}
-(the empty string).
-
-@item overstrike-style=@var{overstrike-option}
-
-Either @code{single} or @code{line}:
-
-@itemize @bullet
-@item
-If @code{single} is selected, then, to overstrike a line of text, the
-output driver will output a character, backspace, overstrike, output a
-character, backspace, overstrike, and so on along a line.
-
-@item
-If @code{line} is selected then the output driver will output an entire
-line, then backspace or emit a carriage return (as indicated by
-@code{carriage-return-style}), then overstrike the entire line at once.
-@end itemize
-
-@code{single} is recommended for use with ttys and programs that
-understand overstriking in text files, such as the pager @code{less}.
-@code{single} will also work with printer devices but results in rapid
-back-and-forth motions of the printhead that can cause the printer to
-physically overheat!
-
-@code{line} is recommended for use with printer devices. Most programs
-that understand overstriking in text files will not properly deal with
-@code{line} mode.
-
-Default: @code{single}.
-
-@item carriage-return-style=@var{carriage-return-type}
-
-Either @code{bs} or @code{cr}. This option applies only when one or
-more of the font commands is set to @code{overstrike} and, at the same
-time, @code{overstrike-style} is set to @code{line}.
-
-@itemize @bullet
-@item
-If @code{bs} is selected then the driver will return to the beginning of
-a line by emitting a sequence of backspace characters (ASCII 8).
-
-@item
-If @code{cr} is selected then the driver will return to the beginning of
-a line by emitting a single carriage-return character (ASCII 13).
-@end itemize
-
-Although @code{cr} is preferred as being more compact, @code{bs} is more
-general since some devices do not interpret carriage returns in the
-desired manner. Default: @code{bs}.
-@end table
-
-@node HTML driver class, Miscellaneous configuring, ASCII driver class, Configuration
-@section The HTML driver class
-
-The @code{html} driver class is used to produce output for viewing in
-tables-capable web browsers such as Emacs' w3-mode. Its configuration
-is very simple. Currently, the output has a very plain format. In the
-future, further work may be done on improving the output appearance.
-
-There are few options for use with the @code{html} driver class:
-
-@table @code
-@item output-file=@var{filename}
-
-File to which output should be sent. This can be an ordinary filename
-(i.e., @code{"pspp.ps"}), a pipe filename (i.e., @code{"|lpr"}), or
-stdout (@code{"-"}). Default: @code{"pspp.html"}.
-
-@item prologue-file=@var{prologue-file-name}
-
-Sets the name of the PostScript prologue file. You can write your own
-prologue if you want to customize colors or other settings: see
-@ref{HTML Prologue}. Default: @code{html-prologue}.
-@end table
-
-@menu
-* HTML Prologue:: Format of the HTML prologue file.
-@end menu
-
-@node HTML Prologue, , HTML driver class, HTML driver class
-@subsection The HTML prologue
-
-HTML files that are generated by PSPP consist of two parts: a prologue
-and a body. The prologue is a collection of boilerplate. Only the body
-differs greatly between two outputs. You can tune the colors and other
-attributes of the output by editing the prologue.
-
-The prologue is dumped into the output stream essentially unmodified.
-However, two actions are performed on its lines. First, certain lines
-may be omitted as specified in the prologue file itself. Second,
-variables are substituted.
-
-The following lines are omitted:
-
-@enumerate
-@item
-All lines that contain three bangs in a row (@code{!!!}).
-
-@item
-Lines that contain @code{!title}, if no title is set for the output. If
-a title is set, then the characters @code{!title} are removed before the
-line is output.
-
-@item
-Lines that contain @code{!subtitle}, if no subtitle is set for the
-output. If a subtitle is set, then the characters @code{!subtitle} are
-removed before the line is output.
-@end enumerate
-
-The following are the variables that are substituted. Only the
-variables listed are substituted; environment variables are not.
-@xref{Environment substitutions}.
-
-@table @code
-@item generator
-
-PSPP version as a string: @samp{GNU PSPP 0.1b}, for example.
-
-@item date
-
-Date the file was created. Example: @samp{Tue May 21 13:46:22 1991}.
-
-@item user
-
-Under multiuser OSes, the user's login name, taken either from the
-environment variable @code{LOGNAME} or, if that fails, the result of the
-C library function @code{getlogin()}. Defaults to @samp{nobody}.
-
-@item host
-
-System hostname as reported by @code{gethostname()}. Defaults to
-@samp{nowhere}.
-
-@item title
-
-Document title as a string. This is the title specified in the PSPP
-syntax file.
-
-@item subtitle
-
-Document subtitle as a string.
-
-@item source-file
-
-PSPP syntax file name. Example: @samp{mary96/first.stat}.
-@end table
-
-@node Miscellaneous configuring, Improving output quality, HTML driver class, Configuration
-@section Miscellaneous configuration
-
-The following environment variables can be used to further configure
-PSPP:
-
-@table @code
-@item HOME
-
-Used to determine the user's home directory. No default value.
-
-@item STAT_INCLUDE_PATH
-
-Path used to find include files in PSPP syntax files. Defaults vary
-across operating systems:
-
-@table @asis
-@item UNIX
-
-@itemize @bullet
-@item
-@file{.}
-
-@item
-@file{~/.pspp/include}
-
-@item
-@file{/usr/local/lib/pspp/include}
-
-@item
-@file{/usr/lib/pspp/include}
-
-@item
-@file{/usr/local/share/pspp/include}
-
-@item
-@file{/usr/share/pspp/include}
-@end itemize
-
-@item MS-DOS
-
-@itemize @bullet
-@item
-@file{.}
-
-@item
-@file{C:\PSPP\INCLUDE}
-
-@item
-@file{$PATH}
-@end itemize
-
-@item Other OSes
-No default path.
-@end table
-
-@item STAT_PAGER
-@itemx PAGER
-
-When PSPP invokes an external pager, it uses the first of these that
-is defined. There is a default pager only if the person who compiled
-PSPP defined one.
-
-@item TERM
-
-The terminal type @code{termcap} or @code{ncurses} will use, if such
-support was compiled into PSPP.
-
-@item STAT_OUTPUT_INIT_FILE
-
-The basename used to search for the driver definition file.
-@xref{Output devices}. @xref{File locations}. Default: @code{devices}.
-
-@item STAT_OUTPUT_PAPERSIZE_FILE
-
-The basename used to search for the papersize file. @xref{papersize}.
-@xref{File locations}. Default: @code{papersize}.
-
-@item STAT_OUTPUT_INIT_PATH
-
-The path used to search for the driver definition file and the papersize
-file. @xref{File locations}. Default: the standard configuration path.
-
-@item TMPDIR
-
-The @code{sort} procedure stores its temporary files in this directory.
-Default: (UNIX) @file{/tmp}, (MS-DOS) @file{\}, (other OSes) empty string.
-
-@item TEMP
-@item TMP
-
-Under MS-DOS only, these variables are consulted after TMPDIR, in this
-order.
-@end table
-
-@node Improving output quality, , Miscellaneous configuring, Configuration
-@section Improving output quality
-
-When its drivers are set up properly, PSPP can produce output that
-looks very good indeed. The PostScript driver, suitably configured, can
-produce presentation-quality output. Here are a few guidelines for
-producing better-looking output, regardless of output driver. Your
-mileage may vary, of course, and everyone has different esthetic
-preferences.
-
-@itemize @bullet
-@item
-Width is important in PSPP output. Greater output width leads to more
-readable output, to a point. Try the following to increase the output
-width:
-
-@itemize @minus
-@item
-If you're using the ASCII driver with a dot-matrix printer, figure out
-what you need to do to put the printer into compressed mode. Put that
-string into the @code{init-string} setting. Try to get 132 columns; 160
-might be better, but you might find that print that tiny is difficult to
-read.
-
-@item
-With the PostScript driver, try these ideas:
-
-@itemize +
-@item
-Landscape mode.
-
-@item
-Legal-size (8.5" x 14") paper in landscape mode.
-
-@item
-Reducing font sizes. If you're using 12-point fonts, try 10 point; if
-you're using 10-point fonts, try 8 point. Some fonts are more readable
-than others at small sizes.
-@end itemize
-@end itemize
-
-Try to strike a balance between character size and page width.
-
-@item
-Use high-quality fonts. Many public domain fonts are poor in quality.
-Recently, URW made some high-quality fonts available under the GPL.
-These are probably suitable.
-
-@item
-Be sure you're using the proper font metrics. The font metrics provided
-with PSPP may not correspond to the fonts actually being printed.
-This can cause bizarre-looking output.
-
-@item
-Make sure that you're using good ink/ribbon/toner. Darker print is
-easier to read.
-
-@item
-Use plain fonts with serifs, such as Times-Roman or Palatino. Avoid
-choosing italic or bold fonts as document base fonts.
-@end itemize
-
-@node Invocation, Language, Configuration, Top
-@chapter Invoking PSPP
-@cindex invocation
-@cindex PSPP, invoking
-
-@cindex command line, options
-@cindex options, command-line
-@example
-pspp [ -B @var{dir} | --config-dir=@var{dir} ] [ -o @var{device} | --device=@var{device} ]
- [ -d @var{var}[=@var{value}] | --define=@var{var}[=@var{value}] ] [-u @var{var} | --undef=@var{var} ]
- [ -f @var{file} | --out-file=@var{file} ] [ -p | --pipe ] [ -I- | --no-include ]
- [ -I @var{dir} | --include=@var{dir} ] [ -i | --interactive ]
- [ -n | --edit | --dry-run | --just-print | --recon ]
- [ -r | --no-statrc ] [ -h | --help ] [ -l | --list ]
- [ -c @var{command} | --command @var{command} ] [ -s | --safer ]
- [ --testing-mode ] [ -V | --version ] [ -v | --verbose ]
- [ @var{key}=@var{value} ] @var{file}@enddots{}
-@end example
-
-@menu
-* Non-option Arguments:: Specifying syntax files and output devices.
-* Configuration Options:: Change the configuration for the current run.
-* Input and output options:: Controlling input and output files.
-* Language control options:: Language variants.
-* Informational options:: Helpful information about PSPP.
-@end menu
-
-@node Non-option Arguments, Configuration Options, Invocation, Invocation
-@section Non-option Arguments
-
-Syntax files and output device substitutions can be specified on
-PSPP's command line:
-
-@table @code
-@item @var{file}
-
-A file by itself on the command line will be executed as a syntax file.
-PSPP terminates after the syntax file runs, unless the @code{-i} or
-@code{--interactive} option is given (@pxref{Language control options}).
-
-@item @var{file1} @var{file2}
-
-When two or more filenames are given on the command line, the first
-syntax file is executed, then PSPP's dictionary is cleared, then the second
-syntax file is executed.
-
-@item @var{file1} + @var{file2}
-
-If syntax files' names are delimited by a plus sign (@samp{+}), then the
-dictionary is not cleared between their executions, as if they were
-concatenated together into a single file.
-
-@item @var{key}=@var{value}
-
-Defines an output device macro @var{key} to expand to @var{value},
-overriding any macro having the same @var{key} defined in the device
-configuration file. @xref{Macro definitions}.
-
-@end table
-
-There is one other way to specify a syntax file, if your operating
-system supports it. If you have a syntax file @file{foobar.stat}, put
-the notation
-
-@example
-#! /usr/local/bin/pspp
-@end example
-
-at the top, and mark the file as executable with @code{chmod +x
-foobar.stat}. (If PSPP is not installed in @file{/usr/local/bin},
-then insert its actual installation directory into the syntax file
-instead.) Now you should be able to invoke the syntax file just by
-typing its name. You can include any options on the command line as
-usual. PSPP entirely ignores any lines beginning with @samp{#!}.
-
-@node Configuration Options, Input and output options, Non-option Arguments, Invocation
-@section Configuration Options
-
-Configuration options are used to change PSPP's configuration for the
-current run. The configuration options are:
-
-@table @code
-@item -a @{compatible|enhanced@}
-@itemx --algorithm=@{compatible|enhanced@}
-
-If you chose @code{compatible}, then PSPP will use the same algorithms
-as used by some proprietary statistical analysis packages.
-This is not recommended, as these algorithms are inferior and in some cases
-compeletely broken.
-The default setting is @code{enhanced}.
-Certain commands have subcommands which allow you to override this setting on
-a per command basis.
-
-@item -B @var{dir}
-@itemx --config-dir=@var{dir}
-
-Sets the configuration directory to @var{dir}. @xref{File locations}.
-
-@item -o @var{device}
-@itemx --device=@var{device}
-
-Selects the output device with name @var{device}. If this option is
-given more than once, then all devices mentioned are selected. This
-option disables all devices besides those mentioned on the command line.
-
-@item -d @var{var}[=@var{value}]
-@itemx --define=@var{var}[=@var{value}]
-
-Defines an `environment variable' named @var{var} having the optional
-value @var{value} specified. @xref{Variable values}.
-
-@item -u @var{var}
-@itemx --undef=@var{var}
-
-Undefines the `environment variable' named @var{var}. @xref{Variable
-values}.
-@end table
-
-@node Input and output options, Language control options, Configuration Options, Invocation
-@section Input and output options
-
-Input and output options affect how PSPP reads input and writes
-output. These are the input and output options:
-
-@table @code
-@item -f @var{file}
-@itemx --out-file=@var{file}
-
-This overrides the output file name for devices designated as listing
-devices. If a file named @var{file} already exists, it is overwritten.
-
-@item -p
-@itemx --pipe
-
-Allows PSPP to be used as a filter by causing the syntax file to be
-read from stdin and output to be written to stdout. Conflicts with the
-@code{-f @var{file}} and @code{--file=@var{file}} options.
-
-@item -I-
-@itemx --no-include
-
-Clears all directories from the include path. This includes all
-directories put in the include path by default. @xref{Miscellaneous
-configuring}.
-
-@item -I @var{dir}
-@itemx --include=@var{dir}
-
-Appends directory @var{dir} to the path that is searched for include
-files in PSPP syntax files.
-
-@item -c @var{command}
-@itemx --command=@var{command}
-
-Execute literal command @var{command}. The command is executed before
-startup syntax files, if any.
-
-@item --testing-mode
-
-Invoke heuristics to assist with testing PSPP. For use by @code{make
-check} and similar scripts.
-@end table
-
-@node Language control options, Informational options, Input and output options, Invocation
-@section Language control options
-
-Language control options control how PSPP syntax files are parsed and
-interpreted. The available language control options are:
-
-@table @code
-@item -i
-@itemx --interactive
-
-When a syntax file is specified on the command line, PSPP normally
-terminates after processing it. Giving this option will cause PSPP to
-bring up a command prompt after processing the syntax file.
-
-In addition, this forces syntax files to be interpreted in interactive
-mode, rather than the default batch mode. @xref{Tokenizing lines}, for
-information on the differences between batch mode and interactive mode
-command interpretation.
-
-@item -n
-@itemx --edit
-@itemx --dry-run
-@itemx --just-print
-@itemx --recon
-
-Only the syntax of any syntax file specified or of commands entered at
-the command line is checked. Transformations are not performed and
-procedures are not executed. Not yet implemented.
-
-@item -r
-@itemx --no-statrc
-
-Prevents the execution of the PSPP startup syntax file. Not yet
-implemented, as startup syntax files aren't, either.
-
-@item -s
-@itemx --safer
-
-Disables certain unsafe operations. This includes the ERASE and
-HOST commands, as well as use of pipes as input and output files.
-@end table
-
-@node Informational options, , Language control options, Invocation
-@section Informational options
-
-Informational options cause information about PSPP to be written to
-the terminal. Here are the available options:
-
-@table @code
-@item -h
-@item --help
-
-Prints a message describing PSPP command-line syntax and the available
-device driver classes, then terminates.
-
-@item -l
-@item --list
-
-Lists the available device driver classes, then terminates.
-
-@item -x @{compatible|enhanced@}
-@itemx --syntax=@{compatible|enhanced@}
-
-If you chose @code{compatible}, then PSPP will only accept command syntax that
-is compatible with the proprietary program SPSS.
-If you choose @code{enhanced} then additional syntax will be available.
-The default is @code{enhanced}.
-
-
-@item -V
-@item --version
-
-Prints a brief message listing PSPP's version, warranties you don't
-have, copying conditions and copyright, and e-mail address for bug
-reports, then terminates.
-
-@item -v
-@item --verbose
-
-Increments PSPP's verbosity level. Higher verbosity levels cause
-PSPP to display greater amounts of information about what it is
-doing. Often useful for debugging PSPP's configuration.
-
-This option can be given multiple times to set the verbosity level to
-that value. The default verbosity level is 0, in which no informational
-messages will be displayed.
-
-Higher verbosity levels cause messages to be displayed when the
-corresponding events take place.
-
-@table @asis
-@item 1
-
-Driver and subsystem initializations.
-
-@item 2
-
-Completion of driver initializations. Beginning of driver closings.
-
-@item 3
-
-Completion of driver closings.
-
-@item 4
-
-Files searched for; success of searches.
-
-@item 5
-
-Individual directories included in file searches.
-@end table
-
-Each verbosity level also includes messages from lower verbosity levels.
-
-@end table
-
-@node Language, Expressions, Invocation, Top
-@chapter The PSPP language
-@cindex language, PSPP
-@cindex PSPP, language
-
-@quotation
-@strong{Please note:} PSPP is not even close to completion.
-Only a few actual statistical procedures are implemented. PSPP
-is a work in progress.
-@end quotation
-
-This chapter discusses elements common to many PSPP commands.
-Later chapters will describe individual commands in detail.
-
-@menu
-* Tokens:: Characters combine to form tokens.
-* Commands:: Tokens combine to form commands.
-* Types of Commands:: Commands come in several flavors.
-* Order of Commands:: Commands combine to form syntax files.
-* Missing Observations:: Handling missing observations.
-* Variables:: The unit of data storage.
-* Files:: Files used by PSPP.
-* BNF:: How command syntax is described.
-@end menu
-
-@node Tokens, Commands, Language, Language
-@section Tokens
-@cindex language, lexical analysis
-@cindex language, tokens
-@cindex tokens
-@cindex lexical analysis
-@cindex lexemes
-
-PSPP divides most syntax file lines into series of short chunks
-called @dfn{tokens}, @dfn{lexical elements}, or @dfn{lexemes}. These
-tokens are then grouped to form commands, each of which tells
-PSPP to take some action---read in data, write out data, perform
-a statistical procedure, etc. The process of dividing input into tokens
-is @dfn{tokenization}, or @dfn{lexical analysis}. Each type of token is
-described below.
-
-@cindex delimiters
-@cindex whitespace
-Tokens must be separated from each other by @dfn{delimiters}.
-Delimiters include whitespace (spaces, tabs, carriage returns, line
-feeds, vertical tabs), punctuation (commas, forward slashes, etc.), and
-operators (plus, minus, times, divide, etc.) Note that while whitespace
-only separates tokens, other delimiters are tokens in themselves.
-
-@table @strong
-@cindex identifiers
-@item Identifiers
-Identifiers are names that specify variable names, commands, or command
-details.
-
-@itemize @bullet
-@item
-The first character in an identifier must be a letter, @samp{#}, or
-@samp{@@}. Some system identifiers begin with @samp{$}, but
-user-defined variables' names may not begin with @samp{$}.
-
-@item
-The remaining characters in the identifier must be letters, digits, or
-one of the following special characters:
-
-@example
-. _ $ # @@
-@end example
-
-@item
-@cindex variable names
-@cindex names, variable
-Variable names may be any length, but only the first 8 characters are
-significant.
-
-@item
-@cindex case-sensitivity
-Identifiers are not case-sensitive: @code{foobar}, @code{Foobar},
-@code{FooBar}, @code{FOOBAR}, and @code{FoObaR} are different
-representations of the same identifier.
-
-@item
-@cindex keywords
-Identifiers other than variable names may be abbreviated to their first
-3 characters if this abbreviation is unambiguous. These identifiers are
-often called @dfn{keywords}. (Unique abbreviations of 3 or more
-characters are also accepted: @samp{FRE}, @samp{FREQ}, and
-@samp{FREQUENCIES} are equivalent when the last is a keyword.)
-
-@item
-Whether an identifier is a keyword depends on the context.
-
-@item
-@cindex keywords, reserved
-@cindex reserved keywords
-Some keywords are reserved. These keywords may not be used in any
-context besides those explicitly described in this manual. The reserved
-keywords are:
-
-@example
-ALL AND BY EQ GE GT LE LT NE NOT OR TO WITH
-@end example
-
-@item
-Since keywords are identifiers, all the rules for identifiers apply.
-Specifically, they must be delimited as are other identifiers:
-@code{WITH} is a reserved keyword, but @code{WITHOUT} is a valid
-variable name.
-@end itemize
-
-@cindex @samp{.}
-@cindex period
-@cindex variable names, ending with period
-@strong{Caution:} It is legal to end a variable name with a period, but
-@emph{don't do it!} The variable name will be misinterpreted when it is
-the final token on a line: @code{FOO.} will be divided into two separate
-tokens, @samp{FOO} and @samp{.}, the @dfn{terminal dot}.
-@xref{Commands, , Forming commands of tokens}.
-
-@item Numbers
-@cindex numbers
-@cindex integers
-@cindex reals
-Numbers may be specified as integers or reals. Integers are internally
-converted into reals. Scientific notation is not supported. Here are
-some examples of valid numbers:
-
-@example
-1234 3.14159265359 .707106781185 8945.
-@end example
-
-@strong{Caution:} The last example will be interpreted as two tokens,
-@samp{8945} and @samp{.}, if it is the last token on a line.
-
-@item Strings
-@cindex strings
-@cindex @samp{'}
-@cindex @samp{"}
-@cindex case-sensitivity
-Strings are literal sequences of characters enclosed in pairs of single
-quotes (@samp{'}) or double quotes (@samp{"}).
-
-@itemize @bullet
-@item
-Whitespace and case of letters @emph{are} significant inside strings.
-@item
-Whitespace characters inside a string are not delimiters.
-@item
-To include single-quote characters in a string, enclose the string in
-double quotes.
-@item
-To include double-quote characters in a string, enclose the string in
-single quotes.
-@item
-It is not possible to put both single- and double-quote characters
-inside one string.
-@end itemize
-
-@item Hexstrings
-@cindex hexstrings
-Hexstrings are string variants that use hex digits to specify
-characters.
-
-@itemize @bullet
-@item
-A hexstring may be used anywhere that an ordinary string is allowed.
-
-@item
-@cindex @samp{X'}
-@cindex @samp{'}
-A hexstring begins with @samp{X'} or @samp{x'}, and ends with @samp{'}.
-
-@cindex whitespace
-@item
-No whitespace is allowed between the initial @samp{X} and @samp{'}.
-
-@item
-Double quotes @samp{"} may be used in place of single quotes @samp{'} if
-done in both places.
-
-@item
-Each pair of hex digits is internally changed into a single character
-with the given value.
-
-@item
-If there is an odd number of hex digits, the missing last digit is
-assumed to be @samp{0}.
-
-@item
-@cindex portability
-@strong{Please note:} Use of hexstrings is nonportable because the same
-numeric values are associated with different glyphs by different
-operating systems. Therefore, their use should be confined to syntax
-files that will not be widely distributed.
-
-@item
-@cindex characters, reserved
-@cindex 0
-@cindex whitespace
-@strong{Please note also:} The character with value 00 is reserved for
-internal use by PSPP. Its use in strings causes an error and
-replacement with a blank space (in ASCII, hex 20, decimal 32).
-@end itemize
-
-@item Punctuation
-@cindex punctuation
-Punctuation separates tokens; punctuators are delimiters. These are the
-punctuation characters:
-
-@example
-, / = ( )
-@end example
-
-@item Operators
-@cindex operators
-Operators describe mathematical operations. Some operators are delimiters:
-
-@example
-( ) + - * / **
-@end example
-
-Many of the above operators are also punctuators. Punctuators are
-distinguished from operators by context.
-
-The other operators are all reserved keywords. None of these are
-delimiters:
-
-@example
-AND EQ GE GT LE LT NE OR
-@end example
-
-@item Terminal Dot
-@cindex terminal dot
-@cindex dot, terminal
-@cindex period
-@cindex @samp{.}
-A period (@samp{.}) at the end of a line (except for whitespace) is one
-type of a @dfn{terminal dot}, although not every terminal dot is a
-period at the end of a line. @xref{Commands, , Forming commands of
-tokens}. A period is a terminal dot @emph{only}
-when it is at the end of a line; otherwise it is part of a
-floating-point number. (A period outside a number in the middle of a
-line is an error.)
-
-@quotation
-@cindex terminal dot, changing
-@cindex dot, terminal, changing
-@strong{Please note:} The character used for the @dfn{terminal dot}
-can be changed with @cmd{SET}'s ENDCMD subcommand (@pxref{SET}). This
-is strongly discouraged, and throughout all the remainder of this
-manual it will be assumed that the default setting is in effect.
-@end quotation
-
-@end table
-
-@node Commands, Types of Commands, Tokens, Language
-@section Forming commands of tokens
-
-@cindex PSPP, command structure
-@cindex language, command structure
-@cindex commands, structure
-
-Most PSPP commands share a common structure, diagrammed below:
-
-@example
-@var{cmd}@dots{} [@var{sbc}[=][@var{spec} [[,]@var{spec}]@dots{}]] [[/[=][@var{spec} [[,]@var{spec}]@dots{}]]@dots{}].
-@end example
-
-@cindex @samp{[ ]}
-In the above, rather daunting, expression, pairs of square brackets
-(@samp{[ ]}) indicate optional elements, and names such as @var{cmd}
-indicate parts of the syntax that vary from command to command.
-Ellipses (@samp{...}) indicate that the preceding part may be repeated
-an arbitrary number of times. Let's pick apart what it says above:
-
-@itemize @bullet
-@cindex commands, names
-@item
-A command begins with a command name of one or more keywords, such as
-@cmd{FREQUENCIES}, @cmd{DATA LIST}, or @cmd{N OF CASES}. @var{cmd}
-may be abbreviated to its first word if that is unambiguous; each word
-in @var{cmd} may be abbreviated to a unique prefix of three or more
-characters as described above.
-
-@cindex subcommands
-@item
-The command name may be followed by one or more @dfn{subcommands}:
-
-@itemize @minus
-@item
-Each subcommand begins with a unique keyword, indicated by @var{sbc}
-above. This is analogous to the command name.
-
-@item
-The subcommand name is optionally followed by an equals sign (@samp{=}).
-
-@item
-Some subcommands accept a series of one or more specifications
-(@var{spec}), optionally separated by commas.
-
-@item
-Each subcommand must be separated from the next (if any) by a forward
-slash (@samp{/}).
-@end itemize
-
-@cindex dot, terminal
-@cindex terminal dot
-@item
-Each command must be terminated with a @dfn{terminal dot}.
-The terminal dot may be given one of three ways:
-
-@itemize @minus
-@item
-(most commonly) A period character at the very end of a line, as
-described above.
-
-@item
-(only if NULLINE is on: @xref{SET, , Setting user preferences}, for more
-details.) A completely blank line.
-
-@item
-(in batch mode only) Any line that is not indented from the left side of
-the page causes a terminal dot to be inserted before that line.
-Therefore, each command begins with a line that is flush left, followed
-by zero or more lines that are indented one or more characters from the
-left margin.
-
-In batch mode, PSPP will ignore a plus sign, minus sign, or period
-(@samp{+}, @samp{@minus{}}, or @samp{.}) as the first character in a
-line. Any of these characters as the first character on a line will
-begin a new command. This allows for visual indentation of a command
-without that command being considered part of the previous command.
-
-PSPP is in batch mode when it is reading input from a file, rather
-than from an interactive user. Note that the other forms of the
-terminal dot may also be used in batch mode.
-
-Sometimes, one encounters syntax files that are intended to be
-interpreted in interactive mode rather than batch mode (for instance,
-this can happen if a session log file is used directly as a syntax
-file). When this occurs, use the @samp{-i} command line option to force
-interpretation in interactive mode (@pxref{Language control options}).
-@end itemize
-@end itemize
-
-PSPP ignores empty commands when they are generated by the above
-rules. Note that, as a consequence of these rules, each command must
-begin on a new line.
-
-@node Types of Commands, Order of Commands, Commands, Language
-@section Types of Commands
-
-Commands in PSPP are divided roughly into six categories:
-
-@table @strong
-@item Utility commands
-@cindex utility commands
-Set or display various global options that affect PSPP operations.
-May appear anywhere in a syntax file. @xref{Utilities, , Utility
-commands}.
-
-@item File definition commands
-@cindex file definition commands
-Give instructions for reading data from text files or from special
-binary ``system files''. Most of these commands discard any previous
-data or variables to replace it with the new data and
-variables. At least one must appear before the first command in any of
-the categories below. @xref{Data Input and Output}.
-
-@item Input program commands
-@cindex input program commands
-Though rarely used, these provide powerful tools for reading data files
-in arbitrary textual or binary formats. @xref{INPUT PROGRAM}.
-
-@item Transformations
-@cindex transformations
-Perform operations on data and write data to output files. Transformations
-are not carried out until a procedure is executed.
-
-@item Restricted transformations
-@cindex restricted transformations
-Same as transformations for most purposes. @xref{Order of Commands}, for a
-detailed description of the differences.
-
-@item Procedures
-@cindex procedures
-Analyze data, writing results of analyses to the listing file. Cause
-transformations specified earlier in the file to be performed. In a
-more general sense, a @dfn{procedure} is any command that causes the
-active file (the data) to be read.
-@end table
-
-@node Order of Commands, Missing Observations, Types of Commands, Language
-@section Order of Commands
-@cindex commands, ordering
-@cindex order of commands
-
-PSPP does not place many restrictions on ordering of commands.
-The main restriction is that variables must be defined with one of the
-file-definition commands before they are otherwise referred to.
-
-Of course, there are specific rules, for those who are interested.
-PSPP possesses five internal states, called initial, INPUT PROGRAM,
-FILE TYPE, transformation, and procedure states. (Please note the
-distinction between the @cmd{INPUT PROGRAM} and @cmd{FILE TYPE}
-@emph{commands} and the INPUT PROGRAM and FILE TYPE @emph{states}.)
-
-PSPP starts up in the initial state. Each successful completion
-of a command may cause a state transition. Each type of command has its
-own rules for state transitions:
-
-@table @strong
-@item Utility commands
-@itemize @bullet
-@item
-Legal in all states.
-@item
-Do not cause state transitions. Exception: when @cmd{N OF CASES}
-is executed in the procedure state, it causes a transition to the
-transformation state.
-@end itemize
-
-@item @cmd{DATA LIST}
-@itemize @bullet
-@item
-Legal in all states.
-@item
-When executed in the initial or procedure state, causes a transition to
-the transformation state.
-@item
-Clears the active file if executed in the procedure or transformation
-state.
-@end itemize
-
-@item @cmd{INPUT PROGRAM}
-@itemize @bullet
-@item
-Invalid in INPUT PROGRAM and FILE TYPE states.
-@item
-Causes a transition to the INPUT PROGRAM state.
-@item
-Clears the active file.
-@end itemize
-
-@item @cmd{FILE TYPE}
-@itemize @bullet
-@item
-Invalid in INPUT PROGRAM and FILE TYPE states.
-@item
-Causes a transition to the FILE TYPE state.
-@item
-Clears the active file.
-@end itemize
-
-@item Other file definition commands
-@itemize @bullet
-@item
-Invalid in INPUT PROGRAM and FILE TYPE states.
-@item
-Cause a transition to the transformation state.
-@item
-Clear the active file, except for @cmd{ADD FILES}, @cmd{MATCH FILES},
-and @cmd{UPDATE}.
-@end itemize
-
-@item Transformations
-@itemize @bullet
-@item
-Invalid in initial and FILE TYPE states.
-@item
-Cause a transition to the transformation state.
-@end itemize
-
-@item Restricted transformations
-@itemize @bullet
-@item
-Invalid in initial, INPUT PROGRAM, and FILE TYPE states.
-@item
-Cause a transition to the transformation state.
-@end itemize
-
-@item Procedures
-@itemize @bullet
-@item
-Invalid in initial, INPUT PROGRAM, and FILE TYPE states.
-@item
-Cause a transition to the procedure state.
-@end itemize
-@end table
-
-@node Missing Observations, Variables, Order of Commands, Language
-@section Handling missing observations
-@cindex missing values
-@cindex values, missing
-
-PSPP includes special support for unknown numeric data values.
-Missing observations are assigned a special value, called the
-@dfn{system-missing value}. This ``value'' actually indicates the
-absence of value; it means that the actual value is unknown. Procedures
-automatically exclude from analyses those observations or cases that
-have missing values. Whether single observations or entire cases are
-excluded depends on the procedure.
-
-The system-missing value exists only for numeric variables. String
-variables always have a defined value, even if it is only a string of
-spaces.
-
-Variables, whether numeric or string, can have designated
-@dfn{user-missing values}. Every user-missing value is an actual value
-for that variable. However, most of the time user-missing values are
-treated in the same way as the system-missing value. String variables
-that are wider than a certain width, usually 8 characters (depending on
-computer architecture), cannot have user-missing values.
-
-For more information on missing values, see the following sections:
-@ref{Variables}, @ref{MISSING VALUES}, @ref{Expressions}. See also the
-documentation on individual procedures for information on how they
-handle missing values.
-
-@node Variables, Files, Missing Observations, Language
-@section Variables
-@cindex variables
-@cindex dictionary
-
-Variables are the basic unit of data storage in PSPP. All the
-variables in a file taken together, apart from any associated data, are
-said to form a @dfn{dictionary}.
-Some details of variables are described in the sections below.
-
-@menu
-* Attributes:: Attributes of variables.
-* System Variables:: Variables automatically defined by PSPP.
-* Sets of Variables:: Lists of variable names.
-* Input/Output Formats:: Input and output formats.
-* Scratch Variables:: Variables deleted by procedures.
-@end menu
-
-@node Attributes, System Variables, Variables, Variables
-@subsection Attributes of Variables
-@cindex variables, attributes of
-@cindex attributes of variables
-Each variable has a number of attributes, including:
-
-@table @strong
-@item Name
-This is an identifier. Each variable must have a different name.
-@xref{Tokens}.
-
-@cindex variables, type
-@cindex type of variables
-@item Type
-Numeric or string.
-
-@cindex variables, width
-@cindex width of variables
-@item Width
-(string variables only) String variables with a width of 8 characters or
-fewer are called @dfn{short string variables}. Short string variables
-can be used in many procedures where @dfn{long string variables} (those
-with widths greater than 8) are not allowed.
-
-@quotation
-@strong{Please note:} Certain systems may consider strings longer than 8
-characters to be short strings. Eight characters represents a minimum
-figure for the maximum length of a short string.
-@end quotation
-
-@item Position
-Variables in the dictionary are arranged in a specific order.
-@cmd{DISPLAY} can be used to show this order: see @ref{DISPLAY}.
-
-@item Initialization
-Either reinitialized to 0 or spaces for each case, or left at its
-existing value. @xref{LEAVE}.
-
-@cindex missing values
-@cindex values, missing
-@item Missing values
-Optionally, up to three values, or a range of values, or a specific
-value plus a range, can be specified as @dfn{user-missing values}.
-There is also a @dfn{system-missing value} that is assigned to an
-observation when there is no other obvious value for that observation.
-Observations with missing values are automatically excluded from
-analyses. User-missing values are actual data values, while the
-system-missing value is not a value at all. @xref{Missing Observations}.
-
-@cindex variable labels
-@cindex labels, variable
-@item Variable label
-A string that describes the variable. @xref{VARIABLE LABELS}.
-
-@cindex value labels
-@cindex labels, value
-@item Value label
-Optionally, these associate each possible value of the variable with a
-string. @xref{VALUE LABELS}.
-
-@cindex print format
-@item Print format
-Display width, format, and (for numeric variables) number of decimal
-places. This attribute does not affect how data are stored, just how
-they are displayed. Example: a width of 8, with 2 decimal places.
-@xref{PRINT FORMATS}.
-
-@cindex write format
-@item Write format
-Similar to print format, but used by certain commands that are
-designed to write to binary files. @xref{WRITE FORMATS}.
-@end table
-
-@node System Variables, Sets of Variables, Attributes, Variables
-@subsection Variables Automatically Defined by PSPP
-@cindex system variables
-@cindex variables, system
-
-There are seven system variables. These are not like ordinary
-variables, as they are not stored in each case. They can only be used
-in expressions. These system variables, whose values and output formats
-cannot be modified, are described below.
-
-@table @code
-@cindex @code{$CASENUM}
-@item $CASENUM
-Case number of the case at the moment. This changes as cases are
-shuffled around.
-
-@cindex @code{$DATE}
-@item $DATE
-Date the PSPP process was started, in format A9, following the
-pattern @code{DD MMM YY}.
-
-@cindex @code{$JDATE}
-@item $JDATE
-Number of days between 15 Oct 1582 and the time the PSPP process
-was started.
-
-@cindex @code{$LENGTH}
-@item $LENGTH
-Page length, in lines, in format F11.
-
-@cindex @code{$SYSMIS}
-@item $SYSMIS
-System missing value, in format F1.
-
-@cindex @code{$TIME}
-@item $TIME
-Number of seconds between midnight 14 Oct 1582 and the time the active file
-was read, in format F20.
-
-@cindex @code{$WIDTH}
-@item $WIDTH
-Page width, in characters, in format F3.
-@end table
-
-@node Sets of Variables, Input/Output Formats, System Variables, Variables
-@subsection Lists of variable names
-@cindex TO convention
-@cindex convention, TO
-
-There are several ways to specify a set of variables:
-
-@enumerate
-@item
-(Most commonly.) List the variable names one after another, optionally
-separating them by commas.
-
-@cindex @code{TO}
-@item
-(This method cannot be used on commands that define the dictionary, such
-as @cmd{DATA LIST}.) The syntax is the names of two existing variables,
-separated by the reserved keyword @code{TO}. The meaning is to include
-every variable in the dictionary between and including the variables
-specified. For instance, if the dictionary contains six variables with
-the names @code{ID}, @code{X1}, @code{X2}, @code{GOAL}, @code{MET}, and
-@code{NEXTGOAL}, in that order, then @code{X2 TO MET} would include
-variables @code{X2}, @code{GOAL}, and @code{MET}.
-
-@item
-(This method can be used only on commands that define the dictionary,
-such as @cmd{DATA LIST}.) It is used to define sequences of variables
-that end in consecutive integers. The syntax is two identifiers that
-end in numbers. This method is best illustrated with examples:
-
-@itemize @bullet
-@item
-The syntax @code{X1 TO X5} defines 5 variables:
-
-@itemize @minus
-@item
-X1
-@item
-X2
-@item
-X3
-@item
-X4
-@item
-X5
-@end itemize
-
-@item
-The syntax @code{ITEM0008 TO ITEM0013} defines 6 variables:
-
-@itemize @minus
-@item
-ITEM0008
-@item
-ITEM0009
-@item
-ITEM0010
-@item
-ITEM0011
-@item
-ITEM0012
-@item
-ITEM0013
-@end itemize
-
-@item
-Each of the syntaxes @code{QUES001 TO QUES9} and @code{QUES6 TO QUES3}
-are invalid, although for different reasons, which should be evident.
-@end itemize
-
-Note that after a set of variables has been defined with @cmd{DATA LIST}
-or another command with this method, the same set can be referenced on
-later commands using the same syntax.
-
-@item
-The above methods can be combined, either one after another or delimited
-by commas. For instance, the combined syntax @code{A Q5 TO Q8 X TO Z}
-is legal as long as each part @code{A}, @code{Q5 TO Q8}, @code{X TO Z}
-is individually legal.
-@end enumerate
-
-@node Input/Output Formats, Scratch Variables, Sets of Variables, Variables
-@subsection Input and Output Formats
-
-Data that PSPP inputs and outputs must have one of a number of formats.
-These formats are described, in general, by a format specification of
-the form @code{NAMEw.d}, where @var{name} is the
-format name and @var{w} is a field width. @var{d} is the optional
-desired number of decimal places, if appropriate. If @var{d} is not
-included then it is assumed to be 0. Some formats do not allow @var{d}
-to be specified.
-
-When an input format is specified on @cmd{DATA LIST} or another
-command, then
-it is converted to an output format for the purposes of @cmd{PRINT}
-and other
-data output commands. For most purposes, input and output formats are
-the same; the salient differences are described below.
-
-Below are listed the input and output formats supported by PSPP. If an
-input format is mapped to a different output format by default, then
-that mapping is indicated with @result{}. Each format has the listed
-bounds on input width (iw) and output width (ow).
-
-The standard numeric input and output formats are given in the following
-table:
-
-@table @asis
-@item Fw.d: 1 <= iw,ow <= 40
-Standard decimal format with @var{d} decimal places. If the number is
-too large to fit within the field width, it is expressed in scientific
-notation (@code{1.2+34}) if w >= 6, with always at least two digits in
-the exponent. When used as an input format, scientific notation is
-allowed but an E or an F must be used to introduce the exponent.
-
-The default output format is the same as the input format, except if
-@var{d} > 1. In that case the output @var{w} is always made to be at
-least 2 + @var{d}.
-
-@item Ew.d: 1 <= iw <= 40; 6 <= ow <= 40
-For input this is equivalent to F format except that no E or F is
-require to introduce the exponent. For output, produces scientific
-notation in the form @code{1.2+34}. There are always at least two
-digits given in the exponent.
-
-The default output @var{w} is the largest of the input @var{w}, the
-input @var{d} + 7, and 10. The default output @var{d} is the input
-@var{d}, but at least 3.
-
-@item COMMAw.d: 1 <= iw,ow <= 40
-Equivalent to F format, except that groups of three digits are
-comma-separated on output. If the number is too large to express in the
-field width, then first commas are eliminated, then if there is still
-not enough space the number is expressed in scientific notation given
-that w >= 6. Commas are allowed and ignored when this is used as an
-input format.
-
-@item DOTw.d: 1 <= iw,ow <= 40
-Equivalent to COMMA format except that the roles of comma and decimal
-point are interchanged. However: If SET /DECIMAL=DOT is in effect, then
-COMMA uses @samp{,} for a decimal point and DOT uses @samp{.} for a
-decimal point.
-
-@item DOLLARw.d: 1 <= iw <= 40; 2 <= ow <= 40
-Equivalent to COMMA format, except that the number is prefixed by a
-dollar sign (@samp{$}) if there is room. On input the value is allowed
-to be prefixed by a dollar sign, which is ignored.
-
-The default output @var{w} is the input @var{w}, but at least 2.
-
-@item PCTw.d: 2 <= iw,ow <= 40
-Equivalent to F format, except that the number is suffixed by a percent
-sign (@samp{%}) if there is room. On input the value is allowed to be
-suffixed by a percent sign, which is ignored.
-
-The default output @var{w} is the input @var{w}, but at least 2.
-
-@item Nw.d: 1 <= iw,ow <= 40
-Only digits are allowed within the field width. The decimal point is
-assumed to be @var{d} digits from the right margin.
-
-The default output format is F with the same @var{w} and @var{d}, except
-if @var{d} > 1. In that case the output @var{w} is always made to be at
-least 2 + @var{d}.
-
-@item Zw.d @result{} F: 1 <= iw,ow <= 40
-Zoned decimal input. If you need to use this then you know how.
-
-@item IBw.d @result{} F: 1 <= iw,ow <= 8
-Integer binary format. The field is interpreted as a fixed-point
-positive or negative binary number in two's-complement notation. The
-location of the decimal point is implied. Endianness is the same as the
-host machine.
-
-The default output format is F8.2 if @var{d} is 0. Otherwise it is F,
-with output @var{w} as 9 + input @var{d} and output @var{d} as input
-@var{d}.
-
-@item PIB @result{} F: 1 <= iw,ow <= 8
-Positive integer binary format. The field is interpreted as a
-fixed-point positive binary number. The location of the decimal point
-is implied. Endianness is teh same as the host machine.
-
-The default output format follows the rules for IB format.
-
-@item Pw.d @result{} F: 1 <= iw,ow <= 16
-Binary coded decimal format. Each byte from left to right, except the
-rightmost, represents two digits. The upper nibble of each byte is more
-significant. The upper nibble of the final byte is the least
-significant digit. The lower nibble of the final byte is the sign; a
-value of D represents a negative sign and all other values are
-considered positive. The decimal point is implied.
-
-The default output format follows the rules for IB format.
-
-@item PKw.d @result{} F: 1 <= iw,ow <= 16
-Positive binary code decimal format. Same as P but the last byte is the
-same as the others.
-
-The default output format follows the rules for IB format.
-
-@item RBw @result{} F: 2 <= iw,ow <= 8
-
-Binary C architecture-dependent ``double'' format. For a standard
-IEEE754 implementation @var{w} should be 8.
-
-The default output format follows the rules for IB format.
-
-@item PIBHEXw.d @result{} F: 2 <= iw,ow <= 16
-PIB format encoded as textual hex digit pairs. @var{w} must be even.
-
-The input width is mapped to a default output width as follows:
-2@result{}4, 4@result{}6, 6@result{}9, 8@result{}11, 10@result{}14,
-12@result{}16, 14@result{}18, 16@result{}21. No allowances are made for
-decimal places.
-
-@item RBHEXw @result{} F: 4 <= iw,ow <= 16
-
-RB format encoded as textual hex digits pairs. @var{w} must be even.
-
-The default output format is F8.2.
-
-@item CCAw.d: 1 <= ow <= 40
-@itemx CCBw.d: 1 <= ow <= 40
-@itemx CCCw.d: 1 <= ow <= 40
-@itemx CCDw.d: 1 <= ow <= 40
-@itemx CCEw.d: 1 <= ow <= 40
-
-User-defined custom currency formats. May not be used as an input
-format. @xref{SET}, for more details.
-@end table
-
-The date and time numeric input and output formats accept a number of
-possible formats. Before describing the formats themselves, some
-definitions of the elements that make up their formats will be helpful:
-
-@table @dfn
-@item leader
-All formats accept an optional whitespace leader.
-
-@item day
-An integer between 1 and 31 representing the day of month.
-
-@item day-count
-An integer representing a number of days.
-
-@item date-delimiter
-One or more characters of whitespace or the following characters:
-@code{- / . ,}
-
-@item month
-A month name in one of the following forms:
-@itemize @bullet
-@item
-An integer between 1 and 12.
-@item
-Roman numerals representing an integer between 1 and 12.
-@item
-At least the first three characters of an English month name (January,
-February, @dots{}).
-@end itemize
-
-@item year
-An integer year number between 1582 and 19999, or between 1 and 199.
-Years between 1 and 199 will have 1900 added.
-
-@item julian
-A single number with a year number in the first 2, 3, or 4 digits (as
-above) and the day number within the year in the last 3 digits.
-
-@item quarter
-An integer between 1 and 4 representing a quarter.
-
-@item q-delimiter
-The letter @samp{Q} or @samp{q}.
-
-@item week
-An integer between 1 and 53 representing a week within a year.
-
-@item wk-delimiter
-The letters @samp{wk} in any case.
-
-@item time-delimiter
-At least one characters of whitespace or @samp{:} or @samp{.}.
-
-@item hour
-An integer greater than 0 representing an hour.
-
-@item minute
-An integer between 0 and 59 representing a minute within an hour.
-
-@item opt-second
-Optionally, a time-delimiter followed by a real number representing a
-number of seconds.
-
-@item hour24
-An integer between 0 and 23 representing an hour within a day.
-
-@item weekday
-At least the first two characters of an English day word.
-
-@item spaces
-Any amount or no amount of whitespace.
-
-@item sign
-An optional positive or negative sign.
-
-@item trailer
-All formats accept an optional whitespace trailer.
-@end table
-
-The date input formats are strung together from the above pieces. On
-output, the date formats are always printed in a single canonical
-manner, based on field width. The date input and output formats are
-described below:
-
-@table @asis
-@item DATEw: 9 <= iw,ow <= 40
-Date format. Input format: leader + day + date-delimiter +
-month + date-delimiter + year + trailer. Output format: DD-MMM-YY for
-@var{w} < 11, DD-MMM-YYYY otherwise.
-
-@item EDATEw: 8 <= iw,ow <= 40
-European date format. Input format same as DATE. Output format:
-DD.MM.YY for @var{w} < 10, DD.MM.YYYY otherwise.
-
-@item SDATEw: 8 <= iw,ow <= 40
-Standard date format. Input format: leader + year + date-delimiter +
-month + date-delimiter + day + trailer. Output format: YY/MM/DD for
-@var{w} < 10, YYYY/MM/DD otherwise.
-
-@item ADATEw: 8 <= iw,ow <= 40
-American date format. Input format: leader + month + date-delimiter +
-day + date-delimiter + year + trailer. Output format: MM/DD/YY for
-@var{w} < 10, MM/DD/YYYY otherwise.
-
-@item JDATEw: 5 <= iw,ow <= 40
-Julian date format. Input format: leader + julian + trailer. Output
-format: YYDDD for @var{w} < 7, YYYYDDD otherwise.
-
-@item QYRw: 4 <= iw <= 40, 6 <= ow <= 40
-Quarter/year format. Input format: leader + quarter + q-delimiter +
-year + trailer. Output format: @samp{Q Q YY}, where the first
-@samp{Q} is one of the digits 1, 2, 3, 4, if @var{w} < 8, @code{Q Q
-YYYY} otherwise.
-
-@item MOYRw: 6 <= iw,ow <= 40
-Month/year format. Input format: leader + month + date-delimiter + year
-+ trailer. Output format: @samp{MMM YY} for @var{w} < 8, @samp{MMM
-YYYY} otherwise.
-
-@item WKYRw: 6 <= iw <= 40, 8 <= ow <= 40
-Week/year format. Input format: leader + week + wk-delimiter + year +
-trailer. Output format: @samp{WW WK YY} for @var{w} < 10, @samp{WW WK
-YYYY} otherwise.
-
-@item DATETIMEw.d: 17 <= iw,ow <= 40
-Date and time format. Input format: leader + day + date-delimiter +
-month + date-delimiter + yaer + time-delimiter + hour24 + time-delimiter
-+ minute + opt-second. Output format: @samp{DD-MMM-YYYY HH:MM}. If
-@var{w} > 19 then seconds @samp{:SS} is added. If @var{w} > 22 and
-@var{d} > 0 then fractional seconds @samp{.SS} are added.
-
-@item TIMEw.d: 5 <= iw,ow <= 40
-Time format. Input format: leader + sign + spaces + hour +
-time-delimiter + minute + opt-second. Output format: @samp{HH:MM}.
-Seconds and fractional seconds are available with @var{w} of at least 8
-and 10, respectively.
-
-@item DTIMEw.d: 1 <= iw <= 40, 8 <= ow <= 40
-Time format with day count. Input format: leader + sign + spaces +
-day-count + time-delimiter + hour + time-delimiter + minute +
-opt-second. Output format: @samp{DD HH:MM}. Seconds and fractional
-seconds are available with @var{w} of at least 8 and 10, respectively.
-
-@item WKDAYw: 2 <= iw,ow <= 40
-A weekday as a number between 1 and 7, where 1 is Sunday. Input format:
-leader + weekday + trailer. Output format: as many characters, in all
-capital letters, of the English name of the weekday as will fit in the
-field width.
-
-@item MONTHw: 3 <= iw,ow <= 40
-A month as a number between 1 and 12, where 1 is January. Input format:
-leader + month + trailer. Output format: as many character, in all
-capital letters, of the English name of the month as will fit in the
-field width.
-@end table
-
-There are only two formats that may be used with string variables:
-
-@table @asis
-@item Aw: 1 <= iw <= 255, 1 <= ow <= 254
-The entire field is treated as a string value.
-
-@item AHEXw @result{} A: 2 <= iw <= 254; 2 <= ow <= 510
-The field is composed of characters in a string encoded as textual hex
-digit pairs.
-
-The default output @var{w} is half the input @var{w}.
-@end table
-
-@node Scratch Variables, , Input/Output Formats, Variables
-@subsection Scratch Variables
-
-Most of the time, variables don't retain their values between cases.
-Instead, either they're being read from a data file or the active file,
-in which case they assume the value read, or, if created with
-@cmd{COMPUTE} or
-another transformation, they're initialized to the system-missing value
-or to blanks, depending on type.
-
-However, sometimes it's useful to have a variable that keeps its value
-between cases. You can do this with @cmd{LEAVE} (@pxref{LEAVE}), or you can
-use a @dfn{scratch variable}. Scratch variables are variables whose
-names begin with an octothorpe (@samp{#}).
-
-Scratch variables have the same properties as variables left with
-@cmd{LEAVE}:
-they retain their values between cases, and for the first case they are
-initialized to 0 or blanks. They have the additional property that they
-are deleted before the execution of any procedure. For this reason,
-scratch variables can't be used for analysis. To obtain the same
-effect, use @cmd{COMPUTE} (@pxref{COMPUTE}) to copy the scratch variable's
-value into an ordinary variable, then analysis that variable.
-
-@node Files, BNF, Variables, Language
-@section Files Used by PSPP
-
-PSPP makes use of many files each time it runs. Some of these it
-reads, some it writes, some it creates. Here is a table listing the
-most important of these files:
-
-@table @strong
-@cindex file, command
-@cindex file, syntax file
-@cindex command file
-@cindex syntax file
-@item command file
-@itemx syntax file
-These names (synonyms) refer to the file that contains instructions to
-PSPP that tell it what to do. The syntax file's name is specified on
-the PSPP command line. Syntax files can also be pulled in with
-@cmd{INCLUDE} (@pxref{INCLUDE}).
-
-@cindex file, data
-@cindex data file
-@item data file
-Data files contain raw data in ASCII format suitable for being read in
-by @cmd{DATA LIST}. Data can be embedded in the syntax
-file with @cmd{BEGIN DATA} and @cmd{END DATA}: this makes the
-syntax file a data file too.
-
-@cindex file, output
-@cindex output file
-@item listing file
-One or more output files are created by PSPP each time it is
-run. The output files receive the tables and charts produced by
-statistical procedures. The output files may be in any number of formats,
-depending on how PSPP is configured.
-
-@cindex active file
-@cindex file, active
-@item active file
-The active file is the ``file'' on which all PSPP procedures
-are performed. The active file contains variable definitions and
-cases. The active file is not necessarily a disk file: it is stored
-in memory if there is room.
-@end table
-
-@node BNF, , Files, Language
-@section Backus-Naur Form
-@cindex BNF
-@cindex Backus-Naur Form
-@cindex command syntax, description of
-@cindex description of command syntax
-
-The syntax of some parts of the PSPP language is presented in this
-manual using the formalism known as @dfn{Backus-Naur Form}, or BNF. The
-following table describes BNF:
-
-@itemize @bullet
-@cindex keywords
-@cindex terminals
-@item
-Words in all-uppercase are PSPP keyword tokens. In BNF, these are
-often called @dfn{terminals}. There are some special terminals, which
-are actually written in lowercase for clarity:
-
-@table @asis
-@cindex @code{number}
-@item @code{number}
-A real number.
-
-@cindex @code{integer}
-@item @code{integer}
-An integer number.
-
-@cindex @code{string}
-@item @code{string}
-A string.
-
-@cindex @code{var-name}
-@item @code{var-name}
-A single variable name.
-
-@cindex operators
-@cindex punctuators
-@item @code{=}, @code{/}, @code{+}, @code{-}, etc.
-Operators and punctuators.
-
-@cindex @code{.}
-@cindex terminal dot
-@cindex dot, terminal
-@item @code{.}
-The terminal dot. This is not necessarily an actual dot in the syntax
-file: @xref{Commands}, for more details.
-@end table
-
-@item
-@cindex productions
-@cindex nonterminals
-Other words in all lowercase refer to BNF definitions, called
-@dfn{productions}. These productions are also known as
-@dfn{nonterminals}. Some nonterminals are very common, so they are
-defined here in English for clarity:
-
-@table @code
-@cindex @code{var-list}
-@item var-list
-A list of one or more variable names or the keyword @code{ALL}.
-
-@cindex @code{expression}
-@item expression
-An expression. @xref{Expressions}, for details.
-@end table
-
-@item
-@cindex @code{::=}
-@cindex ``is defined as''
-@cindex productions
-@samp{::=} means ``is defined as''. The left side of @samp{::=} gives
-the name of the nonterminal being defined. The right side of @samp{::=}
-gives the definition of that nonterminal. If the right side is empty,
-then one possible expansion of that nonterminal is nothing. A BNF
-definition is called a @dfn{production}.
-
-@item
-@cindex terminals and nonterminals, differences
-So, the key difference between a terminal and a nonterminal is that a
-terminal cannot be broken into smaller parts---in fact, every terminal
-is a single token (@pxref{Tokens}). On the other hand, nonterminals are
-composed of a (possibly empty) sequence of terminals and nonterminals.
-Thus, terminals indicate the deepest level of syntax description. (In
-parsing theory, terminals are the leaves of the parse tree; nonterminals
-form the branches.)
-
-@item
-@cindex start symbol
-@cindex symbol, start
-The first nonterminal defined in a set of productions is called the
-@dfn{start symbol}. The start symbol defines the entire syntax for
-that command.
-@end itemize
-
-@node Expressions, Data Input and Output, Language, Top
-@chapter Mathematical Expressions
-@cindex expressions, mathematical
-@cindex mathematical expressions
-
-Some PSPP commands use expressions, which share a common syntax
-among all PSPP commands. Expressions are made up of
-@dfn{operands}, which can be numbers, strings, or variable names,
-separated by @dfn{operators}. There are five types of operators:
-grouping, arithmetic, logical, relational, and functions.
-
-Every operator takes one or more @dfn{arguments} as input and produces
-or @dfn{returns} exactly one result as output. Both strings and numeric
-values can be used as arguments and are produced as results, but each
-operator accepts only specific combinations of numeric and string values
-as arguments. With few exceptions, operator arguments may be
-full-fledged expressions in themselves.
-
-@menu
-* Boolean Values:: Boolean values.
-* Missing Values in Expressions:: Using missing values in expressions.
-* Grouping Operators:: parentheses
-* Arithmetic Operators:: add sub mul div pow
-* Logical Operators:: AND NOT OR
-* Relational Operators:: EQ GE GT LE LT NE
-* Functions:: More-sophisticated operators.
-* Order of Operations:: Operator precedence.
-@end menu
-
-@node Boolean Values, Missing Values in Expressions, Expressions, Expressions
-@section Boolean Values
-@cindex Boolean
-@cindex values, Boolean
-
-Some PSPP operators and expressions work with Boolean values, which
-represent true/false conditions. Booleans have only three possible
-values: 0 (false), 1 (true), and system-missing (unknown).
-System-missing is neither true nor false and indicates that the true
-value is unknown.
-
-Boolean-typed operands or function arguments must take on one of these
-three values. Other values are considered false, but cause an error
-when the expression is evaluated.
-
-Strings and Booleans are not compatible, and neither may be used in
-place of the other.
-
-@node Missing Values in Expressions, Grouping Operators, Boolean Values, Expressions
-@section Missing Values in Expressions
-
-String missing values are not treated specially in expressions. Most
-numeric operators return system-missing when given system-missing
-arguments. Exceptions are listed under particular operator
-descriptions.
-
-User-missing values for numeric variables are always transformed into
-the system-missing value, except inside the arguments to the
-@code{VALUE} and @code{SYSMIS} functions.
-
-The missing-value functions can be used to precisely control how missing
-values are treated in expressions. @xref{Missing Value Functions}, for
-more details.
-
-@node Grouping Operators, Arithmetic Operators, Missing Values in Expressions, Expressions
-@section Grouping Operators
-@cindex parentheses
-@cindex @samp{( )}
-@cindex grouping operators
-@cindex operators, grouping
-
-Parentheses (@samp{()}) are the grouping operators. Surround an
-expression with parentheses to force early evaluation.
-
-Parentheses also surround the arguments to functions, but in that
-situation they act as punctuators, not as operators.
-
-@node Arithmetic Operators, Logical Operators, Grouping Operators, Expressions
-@section Arithmetic Operators
-@cindex operators, arithmetic
-@cindex arithmetic operators
-
-The arithmetic operators take numeric arguments and produce numeric
-results.
-
-@table @code
-@cindex @samp{+}
-@cindex addition
-@item @var{a} + @var{b}
-Adds @var{a} and @var{b}, returning the sum.
-
-@cindex @samp{-}
-@cindex subtraction
-@item @var{a} - @var{b}
-Subtracts @var{b} from @var{a}, returning the difference.
-
-@cindex @samp{*}
-@cindex multiplication
-@item @var{a} * @var{b}
-Multiplies @var{a} and @var{b}, returning the product.
-
-@cindex @samp{/}
-@cindex division
-@item @var{a} / @var{b}
-Divides @var{a} by @var{b}, returning the quotient. If @var{b} is
-zero, the result is system-missing.
-
-@cindex @samp{**}
-@cindex exponentiation
-@item @var{a} ** @var{b}
-Returns the result of raising @var{a} to the power @var{b}. If
-@var{a} is negative and @var{b} is not an integer, the result is
-system-missing. The result of @code{0**0} is system-missing as well.
-
-@cindex @samp{-}
-@cindex negation
-@item - @var{a}
-Reverses the sign of @var{a}.
-@end table
-
-@node Logical Operators, Relational Operators, Arithmetic Operators, Expressions
-@section Logical Operators
-@cindex logical operators
-@cindex operators, logical
-
-@cindex true
-@cindex false
-@cindex Boolean
-@cindex values, system-missing
-@cindex system-missing
-The logical operators take logical arguments and produce logical
-results, meaning ``true or false''. PSPP logical operators are
-not true Boolean operators because they may also result in a
-system-missing value.
-
-@table @code
-@cindex @code{AND}
-@cindex @samp{&}
-@cindex intersection, logical
-@cindex logical intersection
-@item @var{a} AND @var{b}
-@itemx @var{a} & @var{b}
-True if both @var{a} and @var{b} are true, false otherwise. If one
-argument is false, the result is false even if the other is missing. If
-both arguments are missing, the result is missing.
-
-@cindex @code{OR}
-@cindex @samp{|}
-@cindex union, logical
-@cindex logical union
-@item @var{a} OR @var{b}
-@itemx @var{a} | @var{b}
-True if at least one of @var{a} and @var{b} is true. If one argument is
-true, the result is true even if the other argument is missing. If both
-arguments are missing, the result is missing.
-
-@cindex @code{NOT}
-@cindex @samp{~}
-@cindex inversion, logical
-@cindex logical inversion
-@item NOT @var{a}
-@itemx ~ @var{a}
-True if @var{a} is false. If the argument is missing, then the result
-is missing.
-@end table
-
-@node Relational Operators, Functions, Logical Operators, Expressions
-@section Relational Operators
-
-The relational operators take numeric or string arguments and produce Boolean
-results.
-
-Strings cannot be compared to numbers. When strings of different
-lengths are compared, the shorter string is right-padded with spaces
-to match the length of the longer string.
-
-The results of string comparisons, other than tests for equality or
-inequality, are dependent on the character set in use. String
-comparisons are case-sensitive.
-
-@table @code
-@cindex equality, testing
-@cindex testing for equality
-@cindex @code{EQ}
-@cindex @samp{=}
-@item @var{a} EQ @var{b}
-@itemx @var{a} = @var{b}
-True if @var{a} is equal to @var{b}.
-
-@cindex less than or equal to
-@cindex @code{LE}
-@cindex @code{<=}
-@item @var{a} LE @var{b}
-@itemx @var{a} <= @var{b}
-True if @var{a} is less than or equal to @var{b}.
-
-@cindex less than
-@cindex @code{LT}
-@cindex @code{<}
-@item @var{a} LT @var{b}
-@itemx @var{a} < @var{b}
-True if @var{a} is less than @var{b}.
-
-@cindex greater than or equal to
-@cindex @code{GE}
-@cindex @code{>=}
-@item @var{a} GE @var{b}
-@itemx @var{a} >= @var{b}
-True if @var{a} is greater than or equal to @var{b}.
-
-@cindex greater than
-@cindex @code{GT}
-@cindex @samp{>}
-@item @var{a} GT @var{b}
-@itemx @var{a} > @var{b}
-True if @var{a} is greater than @var{b}.
-
-@cindex inequality, testing
-@cindex testing for inequality
-@cindex @code{NE}
-@cindex @code{~=}
-@cindex @code{<>}
-@item @var{a} NE @var{b}
-@itemx @var{a} ~= @var{b}
-@itemx @var{a} <> @var{b}
-True is @var{a} is not equal to @var{b}.
-@end table
-
-@node Functions, Order of Operations, Relational Operators, Expressions
-@section Functions
-@cindex functions
-
-@cindex mathematics
-@cindex operators
-@cindex parentheses
-@cindex @code{(}
-@cindex @code{)}
-@cindex names, of functions
-PSPP functions provide mathematical abilities above and beyond
-those possible using simple operators. Functions have a common
-syntax: each is composed of a function name followed by a left
-parenthesis, one or more arguments, and a right parenthesis. Function
-names are @strong{not} reserved; their names are specially treated
-only when followed by a left parenthesis: @code{EXP(10)} refers to the
-constant value @code{e} raised to the 10th power, but @code{EXP} by
-itself refers to the value of variable EXP.
-
-The sections below describe each function in detail.
-
-@menu
-* Advanced Mathematics:: EXP LG10 LN SQRT
-* Miscellaneous Mathematics:: ABS MOD MOD10 RND TRUNC
-* Trigonometry:: ACOS ARCOS ARSIN ARTAN ASIN ATAN COS SIN TAN
-* Missing Value Functions:: MISSING NMISS NVALID SYSMIS VALUE
-* Pseudo-Random Numbers:: NORMAL UNIFORM
-* Set Membership:: ANY RANGE
-* Statistical Functions:: CFVAR MAX MEAN MIN SD SUM VARIANCE
-* String Functions:: CONCAT INDEX LENGTH LOWER LPAD LTRIM NUMBER
- RINDEX RPAD RTRIM STRING SUBSTR UPCASE
-* Time & Date:: CTIME.xxx DATE.xxx TIME.xxx XDATE.xxx
-* Miscellaneous Functions:: LAG YRMODA
-* Functions Not Implemented:: CDF.xxx CDFNORM IDF.xxx NCDF.xxx PROBIT RV.xxx
-@end menu
-
-@node Advanced Mathematics, Miscellaneous Mathematics, Functions, Functions
-@subsection Advanced Mathematical Functions
-@cindex mathematics, advanced
-
-Advanced mathematical functions take numeric arguments and produce
-numeric results.
-
-@deftypefn {Function} {} EXP (@var{exponent})
-Returns @i{e} (approximately 2.71828) raised to power @var{exponent}.
-@end deftypefn
-
-@cindex logarithms
-@deftypefn {Function} {} LG10 (@var{number})
-Takes the base-10 logarithm of @var{number}. If @var{number} is
-not positive, the result is system-missing.
-@end deftypefn
-
-@deftypefn {Function} {} LN (@var{number})
-Takes the base-@i{e} logarithm of @var{number}. If @var{number} is
-not positive, the result is system-missing.
-@end deftypefn
-
-@cindex square roots
-@deftypefn {Function} {} SQRT (@var{number})
-Takes the square root of @var{number}. If @var{number} is negative,
-the result is system-missing.
-@end deftypefn
-
-@node Miscellaneous Mathematics, Trigonometry, Advanced Mathematics, Functions
-@subsection Miscellaneous Mathematical Functions
-@cindex mathematics, miscellaneous
-
-Miscellaneous mathematical functions take numeric arguments and produce
-numeric results.
-
-@cindex absolute value
-@deftypefn {Function} {} ABS (@var{number})
-Results in the absolute value of @var{number}.
-@end deftypefn
-
-@cindex modulus
-@deftypefn {Function} {} MOD (@var{numerator}, @var{denominator})
-Returns the remainder (modulus) of @var{numerator} divided by
-@var{denominator}. If @var{denominator} is 0, the result is
-system-missing. However, if @var{numerator} is 0 and
-@var{denominator} is system-missing, the result is 0.
-@end deftypefn
-
-@cindex modulus, by 10
-@deftypefn {Function} {} MOD10 (@var{number})
-Returns the remainder when @var{number} is divided by 10. If
-@var{number} is negative, MOD10(@var{number}) is negative or zero.
-@end deftypefn
-
-@cindex rounding
-@deftypefn {Function} {} RND (@var{number})
-Takes the absolute value of @var{number} and rounds it to an integer.
-Then, if @var{number} was negative originally, negates the result.
-@end deftypefn
-
-@cindex truncation
-@deftypefn {Function} {} TRUNC (@var{number})
-Discards the fractional part of @var{number}; that is, rounds
-@var{number} towards zero.
-@end deftypefn
-
-@node Trigonometry, Missing Value Functions, Miscellaneous Mathematics, Functions
-@subsection Trigonometric Functions
-@cindex trigonometry
-
-Trigonometric functions take numeric arguments and produce numeric
-results.
-
-@cindex arccosine
-@cindex inverse cosine
-@deftypefn {Function} {} ARCOS (@var{number})
-Takes the arccosine, in radians, of @var{number}. Results in
-system-missing if @var{number} is not between -1 and 1.
-@end deftypefn
-
-@cindex arcsine
-@cindex inverse sine
-@deftypefn {Function} {} ARSIN (@var{number})
-Takes the arcsine, in radians, of @var{number}. Results in
-system-missing if @var{number} is not between -1 and 1 inclusive.
-@end deftypefn
-
-@cindex arctangent
-@cindex inverse tangent
-@deftypefn {Function} {} ARTAN (@var{number})
-Takes the arctangent, in radians, of @var{number}.
-@end deftypefn
-
-@cindex cosine
-@deftypefn {Function} {} COS (@var{angle})
-Takes the cosine of @var{angle} which should be in radians.
-@end deftypefn
-
-@cindex sine
-@deftypefn {Function} {} SIN (@var{angle})
-Takes the sine of @var{angle} which should be in radians.
-@end deftypefn
-
-@cindex tangent
-@deftypefn {Function} {} TAN (@var{angle})
-Takes the tangent of @var{angle} which should be in radians.
-Results in system-missing at values
-of @var{angle} that are too close to odd multiples of pi/2.
-Portability: none.
-@end deftypefn
-
-@node Missing Value Functions, Pseudo-Random Numbers, Trigonometry, Functions
-@subsection Missing-Value Functions
-@cindex missing values
-@cindex values, missing
-@cindex functions, missing-value
-
-Missing-value functions take various numeric arguments and yield
-various types of results. Note that the normal rules of evaluation
-apply within expression arguments to these functions. In particular,
-user-missing values for numeric variables are converted to
-system-missing values.
-
-@deftypefn {Function} {} MISSING (@var{expr})
-Returns 1 if @var{expr} has the system-missing value, 0 otherwise.
-@end deftypefn
-
-@deftypefn {Function} {} NMISS (@var{expr} [, @var{expr}]@dots{})
-Each argument must be a numeric expression. Returns the number of
-system-missing values in the list. As a special extension,
-the syntax @code{@var{var1} TO @var{var2}} may be used to refer to a
-range of variables; see @ref{Sets of Variables}, for more details.
-@end deftypefn
-
-@deftypefn {Function} {} NVALID (@var{expr} [, @var{expr}]@dots{})
-Each argument must be a numeric expression. Returns the number of
-values in the list that are not system-missing. As a special extension,
-the syntax @code{@var{var1} TO @var{var2}} may be used to refer to a
-range of variables; see @ref{Sets of Variables}, for more details.
-@end deftypefn
-
-@deftypefn {Function} {} SYSMIS (@var{expr})
-When @var{expr} is simply the name of a numeric variable, returns 1 if
-the variable has the system-missing value, 0 if it is user-missing or
-not missing. If given @var{expr} takes another form, results in 1 if
-the value is system-missing, 0 otherwise.
-@end deftypefn
-
-@deftypefn {Function} {} VALUE (@var{variable})
-Prevents the user-missing values of @var{variable} from being
-transformed into system-missing values, and always results in the
-actual value of @var{variable}, whether it is user-missing,
-system-missing or not missing at all.
-@end deftypefn
-
-@node Pseudo-Random Numbers, Set Membership, Missing Value Functions, Functions
-@subsection Pseudo-Random Number Generation Functions
-@cindex random numbers
-@cindex pseudo-random numbers (see random numbers)
-
-Pseudo-random number generation functions take numeric arguments and
-produce numeric results.
-
-PSPP uses the alleged RC4 cipher as a pseudo-random number generator
-(PRNG). The bytes output by this PRNG are system-independent for a
-given random seed, but differences in endianness and floating-point
-formats will make PRNG results differ from system to system. RC4
-should produce high-quality random numbers for simulation purposes.
-(If you're concerned about the quality of the random number generator,
-well, you're using a statistical processing package---analyze it!)
-
-PSPP's implementation of RC4 has not undergone any security auditing.
-Furthermore, various precautions that would be necessary for secure
-operation, such as secure seeding and discarding the first several
-bytes of output, have not been taken. Therefore, PSPP's
-implementation of RC4 should not be used for security purposes.
-
-@cindex random numbers, normally-distributed
-@deftypefn {Function} {} NORMAL (@var{number})
-Results in a random number. Results from @code{NORMAL} are normally
-distributed with a mean of 0 and a standard deviation of @var{number}.
-@end deftypefn
-
-@cindex random numbers, uniformly-distributed
-@deftypefn {Function} {} UNIFORM (@var{number})
-Results in a random number between 0 and @var{number}. Results from
-@code{UNIFORM} are evenly distributed across its entire range. There
-may be a maximum on the largest random number ever generated---this is
-often
-@ifinfo
-2**31-1
-@end ifinfo
-@tex
-$2^{31}-1$
-@end tex
-(2,147,483,647), but it may be orders of magnitude
-higher or lower.
-@end deftypefn
-
-@node Set Membership, Statistical Functions, Pseudo-Random Numbers, Functions
-@subsection Set-Membership Functions
-@cindex set membership
-@cindex membership, of set
-
-Set membership functions determine whether a value is a member of a set.
-They take a set of numeric arguments or a set of string arguments, and
-produce Boolean results.
-
-String comparisons are performed according to the rules given in
-@ref{Relational Operators}.
-
-@deftypefn {Function} {} ANY (@var{value}, @var{set} [, @var{set}]@dots{})
-Results in true if @var{value} is equal to any of the @var{set}
-values. Otherwise, results in false. If @var{value} is
-system-missing, returns system-missing. System-missing values in
-@var{set} do not cause ANY to return system-missing.
-@end deftypefn
-
-@deftypefn {Function} {} RANGE (@var{value}, @var{low}, @var{high} [, @var{low}, @var{high}]@dots{})
-Results in true if @var{value} is in any of the intervals bounded by
-@var{low} and @var{high} inclusive. Otherwise, results in false.
-Each @var{low} must be less than or equal to its corresponding
-@var{high} value. @var{low} and @var{high} must be given in pairs.
-If @var{value} is system-missing, returns system-missing.
-System-missing values in @var{set} do not cause RANGE to return
-system-missing.
-@end deftypefn
-
-@node Statistical Functions, String Functions, Set Membership, Functions
-@subsection Statistical Functions
-@cindex functions, statistical
-@cindex statistics
-
-Statistical functions compute descriptive statistics on a list of
-values. Some statistics can be computed on numeric or string values;
-other can only be computed on numeric values. Their results have the
-same type as their arguments. The current case's weighting factor
-(@pxref{WEIGHT}) has no effect on statistical functions.
-
-@cindex arguments, minimum valid
-@cindex minimum valid number of arguments
-With statistical functions it is possible to specify a minimum number of
-non-missing arguments for the function to be evaluated. To do so,
-append a dot and the number to the function name. For instance, to
-specify a minimum of three valid arguments to the MEAN function, use the
-name @code{MEAN.3}.
-
-@cindex coefficient of variation
-@cindex variation, coefficient of
-@deftypefn {Function} {} CFVAR (@var{number}, @var{number}[, @dots{}])
-Results in the coefficient of variation of the values of @var{number}.
-This function requires at least two valid arguments to give a
-non-missing result. (The coefficient of variation is the standard
-deviation divided by the mean.)
-@end deftypefn
-
-@cindex maximum
-@deftypefn {Function} {} MAX (@var{value}, @var{value}[, @dots{}])
-Results in the value of the greatest @var{value}. The @var{value}s may
-be numeric or string. Although at least two arguments must be given,
-only one need be valid for MAX to give a non-missing result.
-@end deftypefn
-
-@cindex mean
-@deftypefn {Function} {} MEAN (@var{number}, @var{number}[, @dots{}])
-Results in the mean of the values of @var{number}. Although at least
-two arguments must be given, only one need be valid for MEAN to give a
-non-missing result.
-@end deftypefn
-
-@cindex minimum
-@deftypefn {Function} {} MIN (@var{number}, @var{number}[, @dots{}])
-Results in the value of the least @var{value}. The @var{value}s may
-be numeric or string. Although at least two arguments must be given,
-only one need be valid for MAX to give a non-missing result.
-@end deftypefn
-
-@cindex standard deviation
-@cindex deviation, standard
-@deftypefn {Function} {} SD (@var{number}, @var{number}[, @dots{}])
-Results in the standard deviation of the values of @var{number}.
-This function requires at least two valid arguments to give a
-non-missing result.
-@end deftypefn
-
-@cindex sum
-@deftypefn {Function} {} SUM (@var{number}, @var{number}[, @dots{}])
-Results in the sum of the values of @var{number}. Although at least two
-arguments must be given, only one need by valid for SUM to give a
-non-missing result.
-@end deftypefn
-
-@cindex variance
-@deftypefn {Function} {} VARIANCE (@var{number}, @var{number}[, @dots{}])
-Results in the variance of the values of @var{number}. This function
-requires at least two valid arguments to give a non-missing result.
-@end deftypefn
-
-@node String Functions, Time & Date, Statistical Functions, Functions
-@subsection String Functions
-@cindex functions, string
-@cindex string functions
-
-String functions take various arguments and return various results.
-
-@cindex concatenation
-@cindex strings, concatenation of
-@deftypefn {Function} {} CONCAT (@var{string}, @var{string}[, @dots{}])
-Returns a string consisting of each @var{string} in sequence.
-@code{CONCAT("abc", "def", "ghi")} has a value of @code{"abcdefghi"}.
-The resultant string is truncated to a maximum of 255 characters.
-@end deftypefn
-
-@cindex searching strings
-@deftypefn {Function} {} INDEX (@var{haystack}, @var{needle})
-Returns a positive integer indicating the position of the first
-occurrence @var{needle} in @var{haystack}. Returns 0 if @var{haystack}
-does not contain @var{needle}. Returns system-missing if @var{needle}
-is an empty string.
-@end deftypefn
-
-@deftypefn {Function} {} INDEX (@var{haystack}, @var{needle}, @var{divisor})
-Divides @var{needle} into parts, each with length @var{divisor}.
-Searches @var{haystack} for the first occurrence of each part, and
-returns the smallest value. Returns 0 if @var{haystack} does not
-contain any part in @var{needle}. It is an error if @var{divisor}
-cannot be evenly divided into the length of @var{needle}. Returns
-system-missing if @var{needle} is an empty string.
-@end deftypefn
-
-@cindex strings, finding length of
-@deftypefn {Function} {} LENGTH (@var{string})
-Returns the number of characters in @var{string}.
-@end deftypefn
-
-@cindex strings, case of
-@deftypefn {Function} {} LOWER (@var{string})
-Returns a string identical to @var{string} except that all uppercase
-letters are changed to lowercase letters. The definitions of
-``uppercase'' and ``lowercase'' are system-dependent.
-@end deftypefn
-
-@cindex strings, padding
-@deftypefn {Function} {} LPAD (@var{string}, @var{length})
-If @var{string} is at least @var{length} characters in length, returns
-@var{string} unchanged. Otherwise, returns @var{string} padded with
-spaces on the left side to length @var{length}. Returns an empty string
-if @var{length} is system-missing, negative, or greater than 255.
-@end deftypefn
-
-@deftypefn {Function} {} LPAD (@var{string}, @var{length}, @var{padding})
-If @var{string} is at least @var{length} characters in length, returns
-@var{string} unchanged. Otherwise, returns @var{string} padded with
-@var{padding} on the left side to length @var{length}. Returns an empty
-string if @var{length} is system-missing, negative, or greater than 255, or
-if @var{padding} does not contain exactly one character.
-@end deftypefn
-
-@cindex strings, trimming
-@cindex whitespace, trimming
-@deftypefn {Function} {} LTRIM (@var{string})
-Returns @var{string}, after removing leading spaces. Other whitespace,
-such as tabs, carriage returns, line feeds, and vertical tabs, is not
-removed.
-@end deftypefn
-
-@deftypefn {Function} {} LTRIM (@var{string}, @var{padding})
-Returns @var{string}, after removing leading @var{padding} characters.
-If @var{padding} does not contain exactly one character, returns an
-empty string.
-@end deftypefn
-
-@cindex numbers, converting from strings
-@cindex strings, converting to numbers
-@deftypefn {Function} {} NUMBER (@var{string}, @var{format})
-Returns the number produced when @var{string} is interpreted according
-to format specifier @var{format}. If the format width @var{w} is less
-than the length of @var{string}, then only the first @var{w}
-characters in @var{string} are used, e.g.@: @code{NUMBER("123", F3.0)}
-and @code{NUMBER("1234", F3.0)} both have value 123. If @var{w} is
-greater than @var{string}'s length, then it is treated as if it were
-right-padded with spaces. If @var{string} is not in the correct
-format for @var{format}, system-missing is returned.
-@end deftypefn
-
-@cindex strings, searching backwards
-@deftypefn {Function} {} RINDEX (@var{string}, @var{format})
-Returns a positive integer indicating the position of the last
-occurrence of @var{needle} in @var{haystack}. Returns 0 if
-@var{haystack} does not contain @var{needle}. Returns system-missing if
-@var{needle} is an empty string.
-@end deftypefn
-
-@deftypefn {Function} {} RINDEX (@var{haystack}, @var{needle}, @var{divisor})
-Divides @var{needle} into parts, each with length @var{divisor}.
-Searches @var{haystack} for the last occurrence of each part, and
-returns the largest value. Returns 0 if @var{haystack} does not contain
-any part in @var{needle}. It is an error if @var{divisor} cannot be
-evenly divided into the length of @var{needle}. Returns system-missing
-if @var{needle} is an empty string.
-@end deftypefn
-
-@cindex padding strings
-@cindex strings, padding
-@deftypefn {Function} {} RPAD (@var{string}, @var{length})
-If @var{string} is at least @var{length} characters in length, returns
-@var{string} unchanged. Otherwise, returns @var{string} padded with
-spaces on the right to length @var{length}. Returns an empty string if
-@var{length} is system-missing, negative, or greater than 255.
-@end deftypefn
-
-@deftypefn {Function} {} RPAD (@var{string}, @var{length}, @var{padding})
-If @var{string} is at least @var{length} characters in length, returns
-@var{string} unchanged. Otherwise, returns @var{string} padded with
-@var{padding} on the right to length @var{length}. Returns an empty
-string if @var{length} is system-missing, negative, or greater than 255,
-or if @var{padding} does not contain exactly one character.
-@end deftypefn
-
-@cindex strings, trimming
-@cindex whitespace, trimming
-@deftypefn {Function} {} RTRIM (@var{string})
-Returns @var{string}, after removing trailing spaces. Other types of
-whitespace are not removed.
-@end deftypefn
-
-@deftypefn {Function} {} RTRIM (@var{string}, @var{padding})
-Returns @var{string}, after removing trailing @var{padding} characters.
-If @var{padding} does not contain exactly one character, returns an
-empty string.
-@end deftypefn
-
-@cindex strings, converting from numbers
-@cindex numbers, converting to strings
-@deftypefn {Function} {} STRING (@var{number}, @var{format})
-Returns a string corresponding to @var{number} in the format given by
-format specifier @var{format}. For example, @code{STRING(123.56, F5.1)}
-has the value @code{"123.6"}.
-@end deftypefn
-
-@cindex substrings
-@cindex strings, taking substrings of
-@deftypefn {Function} {} SUBSTR (@var{string}, @var{start})
-Returns a string consisting of the value of @var{string} from position
-@var{start} onward. Returns an empty string if @var{start} is system-missing
-or has a value less than 1 or greater than the number of characters in
-@var{string}.
-@end deftypefn
-
-@deftypefn {Function} {} SUBSTR (@var{string}, @var{start}, @var{count})
-Returns a string consisting of the first @var{count} characters from
-@var{string} beginning at position @var{start}. Returns an empty string
-if @var{start} or @var{count} is system-missing, if @var{start} is less
-than 1 or greater than the number of characters in @var{string}, or if
-@var{count} is less than 1. Returns a string shorter than @var{count}
-characters if @var{start} + @var{count} - 1 is greater than the number
-of characters in @var{string}. Examples: @code{SUBSTR("abcdefg", 3, 2)}
-has value @code{"cd"}; @code{SUBSTR("Ben Pfaff", 5, 10)} has the value
-@code{"Pfaff"}.
-@end deftypefn
-
-@cindex case conversion
-@cindex strings, case of
-@deftypefn {Function} {} UPCASE (@var{string})
-Returns @var{string}, changing lowercase letters to uppercase letters.
-@end deftypefn
-
-@node Time & Date, Miscellaneous Functions, String Functions, Functions
-@subsection Time & Date Functions
-@cindex functions, time & date
-@cindex times
-@cindex dates
-
-@cindex dates, legal range of
-The legal range of dates for use in PSPP is 15 Oct 1582
-through 31 Dec 19999.
-
-@cindex arguments, invalid
-@cindex invalid arguments
-@quotation
-@strong{Please note:} Most time & date extraction functions will accept
-invalid arguments:
-
-@itemize @bullet
-@item
-Negative numbers in PSPP time format.
-@item
-Numbers less than 86,400 in PSPP date format.
-@end itemize
-
-However, sensible results are not guaranteed for these invalid values.
-The given equivalents for these functions are definitely not guaranteed
-for invalid values.
-@end quotation
-
-@quotation
-@strong{Please note also:} The time & date construction
-functions @strong{do} produce reasonable and useful results for
-out-of-range values; these are not considered invalid.
-@end quotation
-
-@menu
-* Time & Date Concepts:: How times & dates are defined and represented
-* Time Construction:: TIME.@{DAYS HMS@}
-* Time Extraction:: CTIME.@{DAYS HOURS MINUTES SECONDS@}
-* Date Construction:: DATE.@{DMY MDY MOYR QYR WKYR YRDAY@}
-* Date Extraction:: XDATE.@{DATE HOUR JDAY MDAY MINUTE MONTH
- QUARTER SECOND TDAY TIME WEEK
- WKDAY YEAR@}
-@end menu
-
-@node Time & Date Concepts, Time Construction, Time & Date, Time & Date
-@subsubsection How times & dates are defined and represented
-
-@cindex time, concepts
-@cindex time, intervals
-Times and dates are handled by PSPP as single numbers. A
-@dfn{time} is an interval. PSPP measures times in seconds.
-Thus, the following intervals correspond with the numeric values given:
-
-@example
- 10 minutes 600
- 1 hour 3,600
- 1 day, 3 hours, 10 seconds 97,210
- 40 days 3,456,000
- 10010 d, 14 min, 24 s 864,864,864
-@end example
-
-@cindex dates, concepts
-@cindex time, instants of
-A @dfn{date}, on the other hand, is a particular instant in the past or
-the future. PSPP represents a date as a number of seconds after the
-midnight that separated 8 Oct 1582 and 9 Oct 1582. (Please note that 15
-Oct 1582 immediately followed 9 Oct 1582.) Thus, the midnights before
-the dates given below correspond with the numeric PSPP dates given:
-
-@example
- 15 Oct 1582 86,400
- 4 Jul 1776 6,113,318,400
- 1 Jan 1900 10,010,390,400
- 1 Oct 1978 12,495,427,200
- 24 Aug 1995 13,028,601,600
-@end example
-
-@cindex time, mathematical properties of
-@cindex mathematics, applied to times & dates
-@cindex dates, mathematical properties of
-@noindent
-Please note:
-
-@itemize @bullet
-@item
-A time may be added to, or subtracted from, a date, resulting in a date.
-
-@item
-The difference of two dates may be taken, resulting in a time.
-
-@item
-Two times may be added to, or subtracted from, each other, resulting in
-a time.
-@end itemize
-
-(Adding two dates does not produce a useful result.)
-
-Since times and dates are merely numbers, the ordinary addition and
-subtraction operators are employed for these purposes.
-
-@quotation
-@strong{Please note:} Many dates and times have extremely large
-values---just look at the values above. Thus, it is not a good idea to
-take powers of these values; also, the accuracy of some procedures may
-be affected. If necessary, convert times or dates in seconds to some
-other unit, like days or years, before performing analysis.
-@end quotation
-
-@node Time Construction, Time Extraction, Time & Date Concepts, Time & Date
-@subsubsection Functions that Produce Times
-@cindex times, constructing
-@cindex constructing times
-
-These functions take numeric arguments and produce numeric results in
-PSPP time format.
-
-@cindex days
-@cindex time, in days
-@deftypefn {Function} {} TIME.DAYS (@var{ndays})
-Results in a time value corresponding to @var{ndays} days.
-(@code{TIME.DAYS(@var{x})} is equivalent to @code{@var{x} * 60 * 60 *
-24}.)
-@end deftypefn
-
-@cindex hours-minutes-seconds
-@cindex time, in hours-minutes-seconds
-@deftypefn {Function} {} TIME.HMS (@var{nhours}, @var{nmins}, @var{nsecs})
-Results in a time value corresponding to @var{nhours} hours, @var{nmins}
-minutes, and @var{nsecs} seconds. (@code{TIME.HMS(@var{h}, @var{m},
-@var{s})} is equivalent to @code{@var{h}*60*60 + @var{m}*60 +
-@var{s}}.)
-@end deftypefn
-
-@node Time Extraction, Date Construction, Time Construction, Time & Date
-@subsubsection Functions that Examine Times
-@cindex extraction, of time
-@cindex time examination
-@cindex examination, of times
-@cindex time, lengths of
-
-These functions take numeric arguments in PSPP time format and
-give numeric results.
-
-@cindex days
-@cindex time, in days
-@deftypefn {Function} {} CTIME.DAYS (@var{time})
-Results in the number of days and fractional days in @var{time}.
-(@code{CTIME.DAYS(@var{x})} is equivalent to @code{@var{x}/60/60/24}.)
-@end deftypefn
-
-@cindex hours
-@cindex time, in hours
-@deftypefn {Function} {} CTIME.HOURS (@var{time})
-Results in the number of hours and fractional hours in @var{time}.
-(@code{CTIME.HOURS(@var{x})} is equivalent to @code{@var{x}/60/60}.)
-@end deftypefn
-
-@cindex minutes
-@cindex time, in minutes
-@deftypefn {Function} {} CTIME.MINUTES (@var{time})
-Results in the number of minutes and fractional minutes in @var{time}.
-(@code{CTIME.MINUTES(@var{x})} is equivalent to @code{@var{x}/60}.)
-@end deftypefn
-
-@cindex seconds
-@cindex time, in seconds
-@deftypefn {Function} {} CTIME.SECONDS (@var{time})
-Results in the number of seconds and fractional seconds in @var{time}.
-(@code{CTIME.SECONDS} does nothing; @code{CTIME.SECONDS(@var{x})} is
-equivalent to @code{@var{x}}.)
-@end deftypefn
-
-@node Date Construction, Date Extraction, Time Extraction, Time & Date
-@subsubsection Functions that Produce Dates
-@cindex dates, constructing
-@cindex constructing dates
-
-@cindex arguments, of date construction functions
-These functions take numeric arguments and give numeric results in the
-PSPP date format. Arguments taken by these functions are:
-
-@table @var
-@item day
-Refers to a day of the month between 1 and 31.
-
-@item month
-Refers to a month of the year between 1 and 12.
-
-@item quarter
-Refers to a quarter of the year between 1 and 4. The quarters of the
-year begin on the first days of months 1, 4, 7, and 10.
-
-@item week
-Refers to a week of the year between 1 and 53.
-
-@item yday
-Refers to a day of the year between 1 and 366.
-
-@item year
-Refers to a year between 1582 and 19999.
-@end table
-
-@cindex arguments, invalid
-If these functions' arguments are out-of-range, they are correctly
-normalized before conversion to date format. Non-integers are rounded
-toward zero.
-
-@cindex day-month-year
-@cindex dates, day-month-year
-@deftypefn {Function} {} DATE.DMY (@var{day}, @var{month}, @var{year})
-@deftypefnx {Function} {} DATE.MDY (@var{month}, @var{day}, @var{year})
-Results in a date value corresponding to the midnight before day
-@var{day} of month @var{month} of year @var{year}.
-@end deftypefn
-
-@cindex month-year
-@cindex dates, month-year
-@deftypefn {Function} {} DATE.MOYR (@var{month}, @var{year})
-Results in a date value corresponding to the midnight before the first
-day of month @var{month} of year @var{year}.
-@end deftypefn
-
-@cindex quarter-year
-@cindex dates, quarter-year
-@deftypefn {Function} {} DATE.QYR (@var{quarter}, @var{year})
-Results in a date value corresponding to the midnight before the first
-day of quarter @var{quarter} of year @var{year}.
-@end deftypefn
-
-@cindex week-year
-@cindex dates, week-year
-@deftypefn {Function} {} DATE.WKYR (@var{week}, @var{year})
-Results in a date value corresponding to the midnight before the first
-day of week @var{week} of year @var{year}.
-@end deftypefn
-
-@cindex year-day
-@cindex dates, year-day
-@deftypefn {Function} {} DATE.YRDAY (@var{year}, @var{yday})
-Results in a date value corresponding to the midnight before day
-@var{yday} of year @var{year}.
-@end deftypefn
-
-@node Date Extraction, , Date Construction, Time & Date
-@subsubsection Functions that Examine Dates
-@cindex extraction, of dates
-@cindex date examination
-
-@cindex arguments, of date extraction functions
-These functions take numeric arguments in PSPP date or time
-format and give numeric results. These names are used for arguments:
-
-@table @var
-@item date
-A numeric value in PSPP date format.
-
-@item time
-A numeric value in PSPP time format.
-
-@item time-or-date
-A numeric value in PSPP time or date format.
-@end table
-
-@cindex days
-@cindex dates, in days
-@cindex time, in days
-@deftypefn {Function} {} XDATE.DATE (@var{time-or-date})
-For a time, results in the time corresponding to the number of whole
-days @var{date-or-time} includes. For a date, results in the date
-corresponding to the latest midnight at or before @var{date-or-time};
-that is, gives the date that @var{date-or-time} is in.
-(XDATE.DATE(@var{x}) is equivalent to TRUNC(@var{x}/86400)*86400.)
-Applying this function to a time is a non-portable feature.
-@end deftypefn
-
-@cindex hours
-@cindex dates, in hours
-@cindex time, in hours
-@deftypefn {Function} {} XDATE.HOUR (@var{time-or-date})
-For a time, results in the number of whole hours beyond the number of
-whole days represented by @var{date-or-time}. For a date, results in
-the hour (as an integer between 0 and 23) corresponding to
-@var{date-or-time}. (XDATE.HOUR(@var{x}) is equivalent to
-MOD(TRUNC(@var{x}/3600),24)) Applying this function to a time is a
-non-portable feature.
-@end deftypefn
-
-@cindex day of the year
-@cindex dates, day of the year
-@deftypefn {Function} {} XDATE.JDAY (@var{date})
-Results in the day of the year (as an integer between 1 and 366)
-corresponding to @var{date}.
-@end deftypefn
-
-@cindex day of the month
-@cindex dates, day of the month
-@deftypefn {Function} {} XDATE.MDAY (@var{date})
-Results in the day of the month (as an integer between 1 and 31)
-corresponding to @var{date}.
-@end deftypefn
-
-@cindex minutes
-@cindex dates, in minutes
-@cindex time, in minutes
-@deftypefn {Function} {} XDATE.MINUTE (@var{time-or-date})
-Results in the number of minutes (as an integer between 0 and 59) after
-the last hour in @var{time-or-date}. (XDATE.MINUTE(@var{x}) is
-equivalent to MOD(TRUNC(@var{x}/60),60)) Applying this function to a
-time is a non-portable feature.
-@end deftypefn
-
-@cindex months
-@cindex dates, in months
-@deftypefn {Function} {} XDATE.MONTH (@var{date})
-Results in the month of the year (as an integer between 1 and 12)
-corresponding to @var{date}.
-@end deftypefn
-
-@cindex quarters
-@cindex dates, in quarters
-@deftypefn {Function} {} XDATE.QUARTER (@var{date})
-Results in the quarter of the year (as an integer between 1 and 4)
-corresponding to @var{date}.
-@end deftypefn
-
-@cindex seconds
-@cindex dates, in seconds
-@cindex time, in seconds
-@deftypefn {Function} {} XDATE.SECOND (@var{time-or-date})
-Results in the number of whole seconds after the last whole minute (as
-an integer between 0 and 59) in @var{time-or-date}.
-(XDATE.SECOND(@var{x}) is equivalent to MOD(@var{x}, 60).) Applying
-this function to a time is a non-portable feature.
-@end deftypefn
-
-@cindex days
-@cindex times, in days
-@deftypefn {Function} {} XDATE.TDAY (@var{time})
-Results in the number of whole days (as an integer) in @var{time}.
-(XDATE.TDAY(@var{x}) is equivalent to TRUNC(@var{x}/86400).)
-@end deftypefn
-
-@cindex time
-@cindex dates, time of day
-@deftypefn {Function} {} XDATE.TIME (@var{date})
-Results in the time of day at the instant corresponding to @var{date},
-in PSPP time format. This is the number of seconds since
-midnight on the day corresponding to @var{date}. (XDATE.TIME(@var{x}) is
-equivalent to TRUNC(@var{x}/86400)*86400.)
-@end deftypefn
-
-@cindex week
-@cindex dates, in weeks
-@deftypefn {Function} {} XDATE.WEEK (@var{date})
-Results in the week of the year (as an integer between 1 and 53)
-corresponding to @var{date}.
-@end deftypefn
-
-@cindex day of the week
-@cindex weekday
-@cindex dates, day of the week
-@cindex dates, in weekdays
-@deftypefn {Function} {} XDATE.WKDAY (@var{date})
-Results in the day of week (as an integer between 1 and 7) corresponding
-to @var{date}. The days of the week are:
-
-@table @asis
-@item 1
-Sunday
-@item 2
-Monday
-@item 3
-Tuesday
-@item 4
-Wednesday
-@item 5
-Thursday
-@item 6
-Friday
-@item 7
-Saturday
-@end table
-@end deftypefn
-
-@cindex years
-@cindex dates, in years
-@deftypefn {Function} {} XDATE.YEAR (@var{date})
-Returns the year (as an integer between 1582 and 19999) corresponding to
-@var{date}.
-@end deftypefn
-
-@node Miscellaneous Functions, Functions Not Implemented, Time & Date, Functions
-@subsection Miscellaneous Functions
-@cindex functions, miscellaneous
-
-Miscellaneous functions take various arguments and produce various
-results.
-
-@cindex cross-case function
-@cindex function, cross-case
-@deftypefn {Function} {} LAG (@var{variable})
-@anchor{LAG}
-@var{variable} must be a numeric or string variable name. @code{LAG}
-results in the value of that variable for the case before the current
-one. In case-selection procedures, @code{LAG} results in the value of
-the variable for the last case selected. Results in system-missing (for
-numeric variables) or blanks (for string variables) for the first case
-or before any cases are selected.
-@end deftypefn
-
-@deftypefn {Function} {} LAG (@var{variable}, @var{ncases})
-@var{variable} must be a numeric or string variable name. @var{ncases}
-must be a small positive constant integer, although there is no explicit
-limit. (Use of a large value for @var{ncases} will increase memory
-consumption, since PSPP must keep @var{ncases} cases in memory.)
-@code{LAG (@var{variable}, @var{ncases}} results in the value of
-@var{variable} that is @var{ncases} before the case currently being
-processed. See @code{LAG (@var{variable})} above for more details.
-@end deftypefn
-
-@cindex date, Julian
-@cindex Julian date
-@deftypefn {Function} {} YRMODA (@var{year}, @var{month}, @var{day})
-@var{year} is a year between 0 and 199 or 1582 and 19999. @var{month} is
-a month between 1 and 12. @var{day} is a day between 1 and 31. If
-@var{month} or @var{day} is out-of-range, it changes the next higher
-unit. For instance, a @var{day} of 0 refers to the last day of the
-previous month, and a @var{month} of 13 refers to the first month of the
-next year. @var{year} must be in range. If @var{year} is between 0 and
-199, 1900 is added. @var{year}, @var{month}, and @var{day} must all be
-integers.
-
-@code{YRMODA} results in the number of days between 15 Oct 1582 and
-the date specified, plus one. The date passed to @code{YRMODA} must be
-on or after 15 Oct 1582. 15 Oct 1582 has a value of 1.
-@end deftypefn
-
-@node Functions Not Implemented, , Miscellaneous Functions, Functions
-@subsection Functions Not Implemented
-@cindex functions, not implemented
-@cindex not implemented
-@cindex features, not implemented
-
-These functions are not yet implemented and thus not yet documented,
-since it's a hassle.
-
-@findex CDF.xxx
-@findex CDFNORM
-@findex IDF.xxx
-@findex NCDF.xxx
-@findex PROBIT
-@findex RV.xxx
-
-@itemize @bullet
-@item
-@code{CDF.xxx}
-@item
-@code{CDFNORM}
-@item
-@code{IDF.xxx}
-@item
-@code{NCDF.xxx}
-@item
-@code{PROBIT}
-@item
-@code{RV.xxx}
-@end itemize
-
-@node Order of Operations, , Functions, Expressions
-@section Operator Precedence
-@cindex operator precedence
-@cindex precedence, operator
-@cindex order of operations
-@cindex operations, order of
-
-The following table describes operator precedence. Smaller-numbered
-levels in the table have higher precedence. Within a level, operations
-are performed from left to right, except for level 2 (exponentiation),
-where operations are performed from right to left. If an operator
-appears in the table in two places (@code{-}), the first occurrence is
-unary, the second is binary.
-
-@enumerate
-@item
-@code{( )}
-@item
-@code{**}
-@item
-@code{-}
-@item
-@code{* /}
-@item
-@code{+ -}
-@item
-@code{EQ GE GT LE LT NE}
-@item
-@code{AND NOT OR}
-@end enumerate
-
-@node Data Input and Output, System and Portable Files, Expressions, Top
-@chapter Data Input and Output
-@cindex input
-@cindex output
-@cindex data
-@cindex cases
-@cindex observations
-
-Data are the focus of the PSPP language.
-Each datum belongs to a @dfn{case} (also called an @dfn{observation}).
-Each case represents an individual or `experimental unit'.
-For example, in the results of a survey, the names of the respondents,
-their sex, age @i{etc}. and their responses are all data and the data
-pertaining to single respondent is a case.
-This chapter examines
-the PSPP commands for defining variables and reading and writing data.
-
-@quotation
-@strong{Please note:} Data is not actually read until a procedure is
-executed. These commands tell PSPP how to read data, but they
-do not @emph{cause} PSPP to read data.
-@end quotation
-
-@menu
-* BEGIN DATA:: Embed data within a syntax file.
-* CLEAR TRANSFORMATIONS:: Clear pending transformations.
-* DATA LIST:: Fundamental data reading command.
-* END CASE:: Output the current case.
-* END FILE:: Terminate the current input program.
-* FILE HANDLE:: Support for fixed-length records.
-* INPUT PROGRAM:: Support for complex input programs.
-* LIST:: List cases in the active file.
-* MATRIX DATA:: Read matrices in text format.
-* NEW FILE:: Clear the active file and dictionary.
-* PRINT:: Display values in print formats.
-* PRINT EJECT:: Eject the current page then print.
-* PRINT SPACE:: Print blank lines.
-* REREAD:: Take another look at the previous input line.
-* REPEATING DATA:: Multiple cases on a single line.
-* WRITE:: Display values in write formats.
-@end menu
-
-@node BEGIN DATA, CLEAR TRANSFORMATIONS, Data Input and Output, Data Input and Output
-@section BEGIN DATA
-@vindex BEGIN DATA
-@vindex END DATA
-@cindex Embedding data in syntax files
-@cindex Data, embedding in syntax files
-
-@display
-BEGIN DATA.
-@dots{}
-END DATA.
-@end display
-
-@cmd{BEGIN DATA} and @cmd{END DATA} can be used to embed raw ASCII
-data in a PSPP syntax file. @cmd{DATA LIST} or another input
-procedure must be used before @cmd{BEGIN DATA} (@pxref{DATA LIST}).
-@cmd{BEGIN DATA} and @cmd{END DATA} must be used together. @cmd{END
-DATA} must appear by itself on a single line, with no leading
-whitespace and exactly one space between the words @code{END} and
-@code{DATA}, followed immediately by the terminal dot, like this:
-
-@example
-END DATA.
-@end example
-
-@node CLEAR TRANSFORMATIONS, DATA LIST, BEGIN DATA, Data Input and Output
-@section CLEAR TRANSFORMATIONS
-@vindex CLEAR TRANSFORMATIONS
-
-@display
-CLEAR TRANSFORMATIONS.
-@end display
-
-@cmd{CLEAR TRANSFORMATIONS} clears out all pending
-transformations. It does not cancel the current input program. It is
-valid only when PSPP is interactive, not in syntax files.
-
-@node DATA LIST, END CASE, CLEAR TRANSFORMATIONS, Data Input and Output
-@section DATA LIST
-@vindex DATA LIST
-@cindex reading data from a file
-@cindex data, reading from a file
-@cindex data, embedding in syntax files
-@cindex embedding data in syntax files
-
-Used to read text or binary data, @cmd{DATA LIST} is the most
-fundamental data-reading command. Even the more sophisticated input
-methods use @cmd{DATA LIST} commands as a building block.
-Understanding @cmd{DATA LIST} is important to understanding how to use
-PSPP to read your data files.
-
-There are two major variants of @cmd{DATA LIST}, which are fixed
-format and free format. In addition, free format has a minor variant,
-list format, which is discussed in terms of its differences from vanilla
-free format.
-
-Each form of @cmd{DATA LIST} is described in detail below.
-
-@menu
-* DATA LIST FIXED:: Fixed columnar locations for data.
-* DATA LIST FREE:: Any spacing you like.
-* DATA LIST LIST:: Each case must be on a single line.
-@end menu
-
-@node DATA LIST FIXED, DATA LIST FREE, DATA LIST, DATA LIST
-@subsection DATA LIST FIXED
-@vindex DATA LIST FIXED
-@cindex reading fixed-format data
-@cindex fixed-format data, reading
-@cindex data, fixed-format, reading
-@cindex embedding fixed-format data
-
-@display
-DATA LIST [FIXED]
- @{TABLE,NOTABLE@}
- FILE='filename'
- RECORDS=record_count
- END=end_var
- /[line_no] var_spec@dots{}
-
-where each var_spec takes one of the forms
- var_list start-end [type_spec]
- var_list (fortran_spec)
-@end display
-
-@cmd{DATA LIST FIXED} is used to read data files that have values at fixed
-positions on each line of single-line or multiline records. The
-keyword FIXED is optional.
-
-The FILE subcommand must be used if input is to be taken from an
-external file. It may be used to specify a filename as a string or a
-file handle (@pxref{FILE HANDLE}). If the FILE subcommand is not used,
-then input is assumed to be specified within the command file using
-@cmd{BEGIN DATA}@dots{}@cmd{END DATA} (@pxref{BEGIN DATA}).
-
-The optional RECORDS subcommand, which takes a single integer as an
-argument, is used to specify the number of lines per record. If RECORDS
-is not specified, then the number of lines per record is calculated from
-the list of variable specifications later in @cmd{DATA LIST}.
-
-The END subcommand is only useful in conjunction with @cmd{INPUT
-PROGRAM}. @xref{INPUT PROGRAM}, for details.
-
-@cmd{DATA LIST} can optionally output a table describing how the data file
-will be read. The TABLE subcommand enables this output, and NOTABLE
-disables it. The default is to output the table.
-
-The list of variables to be read from the data list must come last.
-Each line in the data record is introduced by a slash (@samp{/}).
-Optionally, a line number may follow the slash. Following, any number
-of variable specifications may be present.
-
-Each variable specification consists of a list of variable names
-followed by a description of their location on the input line. Sets of
-variables may specified using the @code{DATA LIST} TO convention
-(@pxref{Sets of
-Variables}). There are two ways to specify the location of the variable
-on the line: PSPP style and FORTRAN style.
-
-With PSPP style, the starting column and ending column for the field
-are specified after the variable name, separated by a dash (@samp{-}).
-For instance, the third through fifth columns on a line would be
-specified @samp{3-5}. By default, variables are considered to be in
-@samp{F} format (@pxref{Input/Output Formats}). (This default can be
-changed; see @ref{SET} for more information.)
-
-When using PSPP style, to use a variable format other than the default,
-specify the format type in parentheses after the column numbers. For
-instance, for alphanumeric @samp{A} format, use @samp{(A)}.
-
-In addition, implied decimal places can be specified in parentheses
-after the column numbers. As an example, suppose that a data file has a
-field in which the characters @samp{1234} should be interpreted as
-having the value 12.34. Then this field has two implied decimal places,
-and the corresponding specification would be @samp{(2)}. If a field
-that has implied decimal places contains a decimal point, then the
-implied decimal places are not applied.
-
-Changing the variable format and adding implied decimal places can be
-done together; for instance, @samp{(N,5)}.
-
-When using PSPP style, the input and output width of each variable is
-computed from the field width. The field width must be evenly divisible
-into the number of variables specified.
-
-FORTRAN style is an altogether different approach to specifying field
-locations. With this approach, a list of variable input format
-specifications, separated by commas, are placed after the variable names
-inside parentheses. Each format specifier advances as many characters
-into the input line as it uses.
-
-In addition to the standard format specifiers (@pxref{Input/Output
-Formats}), FORTRAN style defines some extensions:
-
-@table @asis
-@item @code{X}
-Advance the current column on this line by one character position.
-
-@item @code{T}@var{x}
-Set the current column on this line to column @var{x}, with column
-numbers considered to begin with 1 at the left margin.
-
-@item @code{NEWREC}@var{x}
-Skip forward @var{x} lines in the current record, resetting the active
-column to the left margin.
-
-@item Repeat count
-Any format specifier may be preceded by a number. This causes the
-action of that format specifier to be repeated the specified number of
-times.
-
-@item (@var{spec1}, @dots{}, @var{specN})
-Group the given specifiers together. This is most useful when preceded
-by a repeat count. Groups may be nested arbitrarily.
-@end table
-
-FORTRAN and PSPP styles may be freely intermixed. PSPP style leaves the
-active column immediately after the ending column specified. Record
-motion using @code{NEWREC} in FORTRAN style also applies to later
-FORTRAN and PSPP specifiers.
-
-@menu
-* DATA LIST FIXED Examples:: Examples of DATA LIST FIXED.
-@end menu
-
-@node DATA LIST FIXED Examples, , DATA LIST FIXED, DATA LIST FIXED
-@unnumberedsubsubsec Examples
-
-@enumerate
-@item
-@example
-DATA LIST TABLE /NAME 1-10 (A) INFO1 TO INFO3 12-17 (1).
-
-BEGIN DATA.
-John Smith 102311
-Bob Arnold 122015
-Bill Yates 918 6
-END DATA.
-@end example
-
-Defines the following variables:
-
-@itemize @bullet
-@item
-@code{NAME}, a 10-character-wide long string variable, in columns 1
-through 10.
-
-@item
-@code{INFO1}, a numeric variable, in columns 12 through 13.
-
-@item
-@code{INFO2}, a numeric variable, in columns 14 through 15.
-
-@item
-@code{INFO3}, a numeric variable, in columns 16 through 17.
-@end itemize
-
-The @code{BEGIN DATA}/@code{END DATA} commands cause three cases to be
-defined:
-
-@example
-Case NAME INFO1 INFO2 INFO3
- 1 John Smith 10 23 11
- 2 Bob Arnold 12 20 15
- 3 Bill Yates 9 18 6
-@end example
-
-The @code{TABLE} keyword causes PSPP to print out a table
-describing the four variables defined.
-
-@item
-@example
-DAT LIS FIL="survey.dat"
- /ID 1-5 NAME 7-36 (A) SURNAME 38-67 (A) MINITIAL 69 (A)
- /Q01 TO Q50 7-56
- /.
-@end example
-
-Defines the following variables:
-
-@itemize @bullet
-@item
-@code{ID}, a numeric variable, in columns 1-5 of the first record.
-
-@item
-@code{NAME}, a 30-character long string variable, in columns 7-36 of the
-first record.
-
-@item
-@code{SURNAME}, a 30-character long string variable, in columns 38-67 of
-the first record.
-
-@item
-@code{MINITIAL}, a 1-character short string variable, in column 69 of
-the first record.
-
-@item
-Fifty variables @code{Q01}, @code{Q02}, @code{Q03}, @dots{}, @code{Q49},
-@code{Q50}, all numeric, @code{Q01} in column 7, @code{Q02} in column 8,
-@dots{}, @code{Q49} in column 55, @code{Q50} in column 56, all in the second
-record.
-@end itemize
-
-Cases are separated by a blank record.
-
-Data is read from file @file{survey.dat} in the current directory.
-
-This example shows keywords abbreviated to their first 3 letters.
-
-@end enumerate
-
-@node DATA LIST FREE, DATA LIST LIST, DATA LIST FIXED, DATA LIST
-@subsection DATA LIST FREE
-@vindex DATA LIST FREE
-
-@display
-DATA LIST FREE
- [(@{TAB,'c'@}, @dots{})]
- [@{NOTABLE,TABLE@}]
- FILE='filename'
- END=end_var
- /var_spec@dots{}
-
-where each var_spec takes one of the forms
- var_list [(type_spec)]
- var_list *
-@end display
-
-In free format, the input data is, by default, structured as a series
-of fields separated by spaces, tabs, commas, or line breaks. Each
-field's content may be unquoted, or it may be quoted with a pairs of
-apostrophes (@samp{'}) or double quotes (@samp{"}). Unquoted white
-space separates fields but is not part of any field. Any mix of
-spaces, tabs, and line breaks is equivalent to a single space for the
-purpose of separating fields, but consecutive commas will skip a
-field.
-
-Alternatively, delimiters can be specified explicitly, as a
-parenthesized, comma-separated list of single-character strings
-immediately following FREE. The word TAB may also be used to specify
-a tab character as a delimiter. When delimiters are specified
-explicitly, only the given characters, plus line breaks, separate
-fields. Furthermore, leading spaces at the beginnings of fields are
-not trimmed, consecutive delimiters define empty fields, and no form
-of quoting is allowed.
-
-The NOTABLE and TABLE subcommands are as in @cmd{DATA LIST FIXED} above.
-NOTABLE is the default.
-
-The FILE and END subcommands are as in @cmd{DATA LIST FIXED} above.
-
-The variables to be parsed are given as a single list of variable names.
-This list must be introduced by a single slash (@samp{/}). The set of
-variable names may contain format specifications in parentheses
-(@pxref{Input/Output Formats}). Format specifications apply to all
-variables back to the previous parenthesized format specification.
-
-In addition, an asterisk may be used to indicate that all variables
-preceding it are to have input/output format @samp{F8.0}.
-
-Specified field widths are ignored on input, although all normal limits
-on field width apply, but they are honored on output.
-
-@node DATA LIST LIST, , DATA LIST FREE, DATA LIST
-@subsection DATA LIST LIST
-@vindex DATA LIST LIST
-
-@display
-DATA LIST LIST
- [(@{TAB,'c'@}, @dots{})]
- [@{NOTABLE,TABLE@}]
- FILE='filename'
- END=end_var
- /var_spec@dots{}
-
-where each var_spec takes one of the forms
- var_list [(type_spec)]
- var_list *
-@end display
-
-With one exception, @cmd{DATA LIST LIST} is syntactically and
-semantically equivalent to @cmd{DATA LIST FREE}. The exception is
-that each input line is expected to correspond to exactly one input
-record. If more or fewer fields are found on an input line than
-expected, an appropriate diagnostic is issued.
-
-@node END CASE, END FILE, DATA LIST, Data Input and Output
-@section END CASE
-@vindex END CASE
-
-@display
-END CASE.
-@end display
-
-@cmd{END CASE} is used only within @cmd{INPUT PROGRAM} to output the
-current case. @xref{INPUT PROGRAM}, for details.
-
-@node END FILE, FILE HANDLE, END CASE, Data Input and Output
-@section END FILE
-@vindex END FILE
-
-@display
-END FILE.
-@end display
-
-@cmd{END FILE} is used only within @cmd{INPUT PROGRAM} to terminate
-the current input program. @xref{INPUT PROGRAM}.
-
-@node FILE HANDLE, INPUT PROGRAM, END FILE, Data Input and Output
-@section FILE HANDLE
-@vindex FILE HANDLE
-
-@display
-FILE HANDLE handle_name
- /NAME='filename'
- /MODE=@{CHARACTER,IMAGE@}
- /LRECL=rec_len
- /TABWIDTH=tab_width
-@end display
-
-Use @cmd{FILE HANDLE} to associate a file handle name with a file and
-its attributes, so that later commands can refer to the file by its
-handle name. Because names of text files can be specified directly on
-commands that access files, @cmd{FILE HANDLE} is only needed when a
-file is not an ordinary file containing lines of text. However,
-@cmd{FILE HANDLE} may be used even for text files, and it may be
-easier to specify a file's name once and later refer to it by an
-abstract handle.
-
-Specify the file handle name as an identifier. Any given identifier may
-only appear once in a PSPP run. File handles may not be reassigned to a
-different file. The file handle name must immediately follow the @cmd{FILE
-HANDLE} command name.
-
-The NAME subcommand specifies the name of the file associated with the
-handle. It is the only required subcommand.
-
-MODE specifies a file mode. In CHARACTER mode, the default, the data
-file is opened in ANSI C text mode, so that local end of line
-conventions are followed, and each text line is read as one record.
-In CHARACTER mode, most input programs will expand tabs to spaces
-(@cmd{DATA LIST FREE} with explicitly specified delimiters is an
-exception). By default, each tab is 4 characters wide, but an
-alternate width may be specified on TABWIDTH. A tab width of 0
-suppresses tab expansion entirely.
-
-By contrast, in BINARY mode, the data file is opened in ANSI C binary
-mode and records are a fixed length. In BINARY mode, LRECL specifies
-the record length in bytes, with a default of 1024. Tab characters
-are never expanded to spaces in binary mode.
-
-@node INPUT PROGRAM, LIST, FILE HANDLE, Data Input and Output
-@section INPUT PROGRAM
-@vindex INPUT PROGRAM
-
-@display
-INPUT PROGRAM.
-@dots{} input commands @dots{}
-END INPUT PROGRAM.
-@end display
-
-@cmd{INPUT PROGRAM}@dots{}@cmd{END INPUT PROGRAM} specifies a
-complex input program. By placing data input commands within @cmd{INPUT
-PROGRAM}, PSPP programs can take advantage of more complex file
-structures than available with only @cmd{DATA LIST}.
-
-The first sort of extended input program is to simply put multiple @cmd{DATA
-LIST} commands within the @cmd{INPUT PROGRAM}. This will cause all of
-the data
-files to be read in parallel. Input will stop when end of file is
-reached on any of the data files.
-
-Transformations, such as conditional and looping constructs, can also be
-included within @cmd{INPUT PROGRAM}. These can be used to combine input
-from several data files in more complex ways. However, input will still
-stop when end of file is reached on any of the data files.
-
-To prevent @cmd{INPUT PROGRAM} from terminating at the first end of
-file, use
-the END subcommand on @cmd{DATA LIST}. This subcommand takes a
-variable name,
-which should be a numeric scratch variable (@pxref{Scratch Variables}).
-(It need not be a scratch variable but otherwise the results can be
-surprising.) The value of this variable is set to 0 when reading the
-data file, or 1 when end of file is encountered.
-
-Two additional commands are useful in conjunction with @cmd{INPUT PROGRAM}.
-@cmd{END CASE} is the first. Normally each loop through the
-@cmd{INPUT PROGRAM}
-structure produces one case. @cmd{END CASE} controls exactly
-when cases are output. When @cmd{END CASE} is used, looping from the end of
-@cmd{INPUT PROGRAM} to the beginning does not cause a case to be output.
-
-@cmd{END FILE} is the second. When the END subcommand is used on @cmd{DATA
-LIST}, there is no way for the @cmd{INPUT PROGRAM} construct to stop
-looping,
-so an infinite loop results. @cmd{END FILE}, when executed,
-stops the flow of input data and passes out of the @cmd{INPUT PROGRAM}
-structure.
-
-All this is very confusing. A few examples should help to clarify.
-
-@example
-INPUT PROGRAM.
- DATA LIST NOTABLE FILE='a.data'/X 1-10.
- DATA LIST NOTABLE FILE='b.data'/Y 1-10.
-END INPUT PROGRAM.
-LIST.
-@end example
-
-The example above reads variable X from file @file{a.data} and variable
-Y from file @file{b.data}. If one file is shorter than the other then
-the extra data in the longer file is ignored.
-
-@example
-INPUT PROGRAM.
- NUMERIC #A #B.
-
- DO IF NOT #A.
- DATA LIST NOTABLE END=#A FILE='a.data'/X 1-10.
- END IF.
- DO IF NOT #B.
- DATA LIST NOTABLE END=#B FILE='b.data'/Y 1-10.
- END IF.
- DO IF #A AND #B.
- END FILE.
- END IF.
- END CASE.
-END INPUT PROGRAM.
-LIST.
-@end example
-
-The above example reads variable X from @file{a.data} and variable Y from
-@file{b.data}. If one file is shorter than the other then the missing
-field is set to the system-missing value alongside the present value for
-the remaining length of the longer file.
-
-@example
-INPUT PROGRAM.
- NUMERIC #A #B.
-
- DO IF #A.
- DATA LIST NOTABLE END=#B FILE='b.data'/X 1-10.
- DO IF #B.
- END FILE.
- ELSE.
- END CASE.
- END IF.
- ELSE.
- DATA LIST NOTABLE END=#A FILE='a.data'/X 1-10.
- DO IF NOT #A.
- END CASE.
- END IF.
- END IF.
-END INPUT PROGRAM.
-LIST.
-@end example
-
-The above example reads data from file @file{a.data}, then from
-@file{b.data}, and concatenates them into a single active file.
-
-@example
-INPUT PROGRAM.
- NUMERIC #EOF.
-
- LOOP IF NOT #EOF.
- DATA LIST NOTABLE END=#EOF FILE='a.data'/X 1-10.
- DO IF NOT #EOF.
- END CASE.
- END IF.
- END LOOP.
-
- COMPUTE #EOF = 0.
- LOOP IF NOT #EOF.
- DATA LIST NOTABLE END=#EOF FILE='b.data'/X 1-10.
- DO IF NOT #EOF.
- END CASE.
- END IF.
- END LOOP.
-
- END FILE.
-END INPUT PROGRAM.
-LIST.
-@end example
-
-The above example does the same thing as the previous example, in a
-different way.
-
-@example
-INPUT PROGRAM.
- LOOP #I=1 TO 50.
- COMPUTE X=UNIFORM(10).
- END CASE.
- END LOOP.
- END FILE.
-END INPUT PROGRAM.
-LIST/FORMAT=NUMBERED.
-@end example
-
-The above example causes an active file to be created consisting of 50
-random variates between 0 and 10.
-
-@node LIST, MATRIX DATA, INPUT PROGRAM, Data Input and Output
-@section LIST
-@vindex LIST
-
-@display
-LIST
- /VARIABLES=var_list
- /CASES=FROM start_index TO end_index BY incr_index
- /FORMAT=@{UNNUMBERED,NUMBERED@} @{WRAP,SINGLE@}
- @{NOWEIGHT,WEIGHT@}
-@end display
-
-The @cmd{LIST} procedure prints the values of specified variables to the
-listing file.
-
-The VARIABLES subcommand specifies the variables whose values are to be
-printed. Keyword VARIABLES is optional. If VARIABLES subcommand is not
-specified then all variables in the active file are printed.
-
-The CASES subcommand can be used to specify a subset of cases to be
-printed. Specify FROM and the case number of the first case to print,
-TO and the case number of the last case to print, and BY and the number
-of cases to advance between printing cases, or any subset of those
-settings. If CASES is not specified then all cases are printed.
-
-The FORMAT subcommand can be used to change the output format. NUMBERED
-will print case numbers along with each case; UNNUMBERED, the default,
-causes the case numbers to be omitted. The WRAP and SINGLE settings are
-currently not used. WEIGHT will cause case weights to be printed along
-with variable values; NOWEIGHT, the default, causes case weights to be
-omitted from the output.
-
-Case numbers start from 1. They are counted after all transformations
-have been considered.
-
-@cmd{LIST} attempts to fit all the values on a single line. If needed
-to make them fit, variable names are displayed vertically. If values
-cannot fit on a single line, then a multi-line format will be used.
-
-@cmd{LIST} is a procedure. It causes the data to be read.
-
-@node MATRIX DATA, NEW FILE, LIST, Data Input and Output
-@section MATRIX DATA
-@vindex MATRIX DATA
-
-@display
-MATRIX DATA
- /VARIABLES=var_list
- /FILE='filename'
- /FORMAT=@{LIST,FREE@} @{LOWER,UPPER,FULL@} @{DIAGONAL,NODIAGONAL@}
- /SPLIT=@{new_var,var_list@}
- /FACTORS=var_list
- /CELLS=n_cells
- /N=n
- /CONTENTS=@{N_VECTOR,N_SCALAR,N_MATRIX,MEAN,STDDEV,COUNT,MSE,
- DFE,MAT,COV,CORR,PROX@}
-@end display
-
-@cmd{MATRIX DATA} command reads square matrices in one of several textual
-formats. @cmd{MATRIX DATA} clears the dictionary and replaces it and
-reads a
-data file.
-
-Use VARIABLES to specify the variables that form the rows and columns of
-the matrices. You may not specify a variable named @code{VARNAME_}. You
-should specify VARIABLES first.
-
-Specify the file to read on FILE, either as a file name string or a file
-handle (@pxref{FILE HANDLE}). If FILE is not specified then matrix data
-must immediately follow @cmd{MATRIX DATA} with a @cmd{BEGIN
-DATA}@dots{}@cmd{END DATA}
-construct (@pxref{BEGIN DATA}).
-
-The FORMAT subcommand specifies how the matrices are formatted. LIST,
-the default, indicates that there is one line per row of matrix data;
-FREE allows single matrix rows to be broken across multiple lines. This
-is analogous to the difference between @cmd{DATA LIST FREE} and
-@cmd{DATA LIST LIST}
-(@pxref{DATA LIST}). LOWER, the default, indicates that the lower
-triangle of the matrix is given; UPPER indicates the upper triangle; and
-FULL indicates that the entire matrix is given. DIAGONAL, the default,
-indicates that the diagonal is part of the data; NODIAGONAL indicates
-that it is omitted. DIAGONAL/NODIAGONAL have no effect when FULL is
-specified.
-
-The SPLIT subcommand is used to specify @cmd{SPLIT FILE} variables for the
-input matrices (@pxref{SPLIT FILE}). Specify either a single variable
-not specified on VARIABLES, or one or more variables that are specified
-on VARIABLES. In the former case, the SPLIT values are not present in
-the data and ROWTYPE_ may not be specified on VARIABLES. In the latter
-case, the SPLIT values are present in the data.
-
-Specify a list of factor variables on FACTORS. Factor variables must
-also be listed on VARIABLES. Factor variables are used when there are
-some variables where, for each possible combination of their values,
-statistics on the matrix variables are included in the data.
-
-If FACTORS is specified and ROWTYPE_ is not specified on VARIABLES, the
-CELLS subcommand is required. Specify the number of factor variable
-combinations that are given. For instance, if factor variable A has 2
-values and factor variable B has 3 values, specify 6.
-
-The N subcommand specifies a population number of observations. When N
-is specified, one N record is output for each @cmd{SPLIT FILE}.
-
-Use CONTENTS to specify what sort of information the matrices include.
-Each possible option is described in more detail below. When ROWTYPE_
-is specified on VARIABLES, CONTENTS is optional; otherwise, if CONTENTS
-is not specified then /CONTENTS=CORR is assumed.
-
-@table @asis
-@item N
-@item N_VECTOR
-Number of observations as a vector, one value for each variable.
-@item N_SCALAR
-Number of observations as a single value.
-@item N_MATRIX
-Matrix of counts.
-@item MEAN
-Vector of means.
-@item STDDEV
-Vector of standard deviations.
-@item COUNT
-Vector of counts.
-@item MSE
-Vector of mean squared errors.
-@item DFE
-Vector of degrees of freedom.
-@item MAT
-Generic matrix.
-@item COV
-Covariance matrix.
-@item CORR
-Correlation matrix.
-@item PROX
-Proximities matrix.
-@end table
-
-The exact semantics of the matrices read by @cmd{MATRIX DATA} are complex.
-Right now @cmd{MATRIX DATA} isn't too useful due to a lack of procedures
-accepting or producing related data, so these semantics aren't
-documented. Later, they'll be described here in detail.
-
-@node NEW FILE, PRINT, MATRIX DATA, Data Input and Output
-@section NEW FILE
-@vindex NEW FILE
-
-@display
-NEW FILE.
-@end display
-
-@cmd{NEW FILE} command clears the current active file.
-
-@node PRINT, PRINT EJECT, NEW FILE, Data Input and Output
-@section PRINT
-@vindex PRINT
-
-@display
-PRINT
- OUTFILE='filename'
- RECORDS=n_lines
- @{NOTABLE,TABLE@}
- /[line_no] arg@dots{}
-
-arg takes one of the following forms:
- 'string' [start-end]
- var_list start-end [type_spec]
- var_list (fortran_spec)
- var_list *
-@end display
-
-The @cmd{PRINT} transformation writes variable data to an output file.
-@cmd{PRINT} is executed when a procedure causes the data to be read.
-Follow @cmd{PRINT} by @cmd{EXECUTE} to print variable data without
-invoking a procedure (@pxref{EXECUTE}).
-
-All @cmd{PRINT} subcommands are optional.
-
-The OUTFILE subcommand specifies the file to receive the output. The
-file may be a file name as a string or a file handle (@pxref{FILE
-HANDLE}). If OUTFILE is not present then output will be sent to PSPP's
-output listing file.
-
-The RECORDS subcommand specifies the number of lines to be output. The
-number of lines may optionally be surrounded by parentheses.
-
-TABLE will cause the PRINT command to output a table to the listing file
-that describes what it will print to the output file. NOTABLE, the
-default, suppresses this output table.
-
-Introduce the strings and variables to be printed with a slash
-(@samp{/}). Optionally, the slash may be followed by a number
-indicating which output line will be specified. In the absence of this
-line number, the next line number will be specified. Multiple lines may
-be specified using multiple slashes with the intended output for a line
-following its respective slash.
-
-Literal strings may be printed. Specify the string itself. Optionally
-the string may be followed by a column number or range of column
-numbers, specifying the location on the line for the string to be
-printed. Otherwise, the string will be printed at the current position
-on the line.
-
-Variables to be printed can be specified in the same ways as available
-for @cmd{DATA LIST FIXED} (@pxref{DATA LIST FIXED}). In addition, a
-variable
-list may be followed by an asterisk (@samp{*}), which indicates that the
-variables should be printed in their dictionary print formats, separated
-by spaces. A variable list followed by a slash or the end of command
-will be interpreted the same way.
-
-If a FORTRAN type specification is used to move backwards on the current
-line, then text is written at that point on the line, the line will be
-truncated to that length, although additional text being added will
-again extend the line to that length.
-
-@node PRINT EJECT, PRINT SPACE, PRINT, Data Input and Output
-@section PRINT EJECT
-@vindex PRINT EJECT
-
-@display
-PRINT EJECT
- OUTFILE='filename'
- RECORDS=n_lines
- @{NOTABLE,TABLE@}
- /[line_no] arg@dots{}
-
-arg takes one of the following forms:
- 'string' [start-end]
- var_list start-end [type_spec]
- var_list (fortran_spec)
- var_list *
-@end display
-
-@cmd{PRINT EJECT} writes data to an output file. Before the data is
-written, the current page in the listing file is ejected.
-
-@xref{PRINT}, for more information on syntax and usage.
-
-@node PRINT SPACE, REREAD, PRINT EJECT, Data Input and Output
-@section PRINT SPACE
-@vindex PRINT SPACE
-
-@display
-PRINT SPACE OUTFILE='filename' n_lines.
-@end display
-
-@cmd{PRINT SPACE} prints one or more blank lines to an output file.
-
-The OUTFILE subcommand is optional. It may be used to direct output to
-a file specified by file name as a string or file handle (@pxref{FILE
-HANDLE}). If OUTFILE is not specified then output will be directed to
-the listing file.
-
-n_lines is also optional. If present, it is an expression
-(@pxref{Expressions}) specifying the number of blank lines to be
-printed. The expression must evaluate to a nonnegative value.
-
-@node REREAD, REPEATING DATA, PRINT SPACE, Data Input and Output
-@section REREAD
-@vindex REREAD
-
-@display
-REREAD FILE=handle COLUMN=column.
-@end display
-
-The @cmd{REREAD} transformation allows the previous input line in a
-data file
-already processed by @cmd{DATA LIST} or another input command to be re-read
-for further processing.
-
-The FILE subcommand, which is optional, is used to specify the file to
-have its line re-read. The file must be specified in the form of a file
-handle (@pxref{FILE HANDLE}). If FILE is not specified then the last
-file specified on @cmd{DATA LIST} will be assumed (last file specified
-lexically, not in terms of flow-of-control).
-
-By default, the line re-read is re-read in its entirety. With the
-COLUMN subcommand, a prefix of the line can be exempted from
-re-reading. Specify an expression (@pxref{Expressions}) evaluating to
-the first column that should be included in the re-read line. Columns
-are numbered from 1 at the left margin.
-
-Issuing @code{REREAD} multiple times will not back up in the data
-file. Instead, it will re-read the same line multiple times.
-
-@node REPEATING DATA, WRITE, REREAD, Data Input and Output
-@section REPEATING DATA
-@vindex REPEATING DATA
-
-@display
-REPEATING DATA
- /STARTS=start-end
- /OCCURS=n_occurs
- /FILE='filename'
- /LENGTH=length
- /CONTINUED[=cont_start-cont_end]
- /ID=id_start-id_end=id_var
- /@{TABLE,NOTABLE@}
- /DATA=var_spec@dots{}
-
-where each var_spec takes one of the forms
- var_list start-end [type_spec]
- var_list (fortran_spec)
-@end display
-
-@cmd{REPEATING DATA} parses groups of data repeating in
-a uniform format, possibly with several groups on a single line. Each
-group of data corresponds with one case. @cmd{REPEATING DATA} may only be
-used within an @cmd{INPUT PROGRAM} structure (@pxref{INPUT PROGRAM}).
-When used with @cmd{DATA LIST}, it
-can be used to parse groups of cases that share a subset of variables
-but differ in their other data.
-
-The STARTS subcommand is required. Specify a range of columns, using
-literal numbers or numeric variable names. This range specifies the
-columns on the first line that are used to contain groups of data. The
-ending column is optional. If it is not specified, then the record
-width of the input file is used. For the inline file (@pxref{BEGIN
-DATA}) this is 80 columns; for a file with fixed record widths it is the
-record width; for other files it is 1024 characters by default.
-
-The OCCURS subcommand is required. It must be a number or the name of a
-numeric variable. Its value is the number of groups present in the
-current record.
-
-The DATA subcommand is required. It must be the last subcommand
-specified. It is used to specify the data present within each repeating
-group. Column numbers are specified relative to the beginning of a
-group at column 1. Data is specified in the same way as with @cmd{DATA LIST
-FIXED} (@pxref{DATA LIST FIXED}).
-
-All other subcommands are optional.
-
-FILE specifies the file to read, either a file name as a string or a
-file handle (@pxref{FILE HANDLE}). If FILE is not present then the
-default is the last file handle used on @cmd{DATA LIST} (lexically, not in
-terms of flow of control).
-
-By default @cmd{REPEATING DATA} will output a table describing how it will
-parse the input data. Specifying NOTABLE will disable this behavior;
-specifying TABLE will explicitly enable it.
-
-The LENGTH subcommand specifies the length in characters of each group.
-If it is not present then length is inferred from the DATA subcommand.
-LENGTH can be a number or a variable name.
-
-Normally all the data groups are expected to be present on a single
-line. Use the CONTINUED command to indicate that data can be continued
-onto additional lines. If data on continuation lines starts at the left
-margin and continues through the entire field width, no column
-specifications are necessary on CONTINUED. Otherwise, specify the
-possible range of columns in the same way as on STARTS.
-
-When data groups are continued from line to line, it is easy
-for cases to get out of sync through careless hand editing. The
-ID subcommand allows a case identifier to be present on each line of
-repeating data groups. @cmd{REPEATING DATA} will check for the same
-identifier on each line and report mismatches. Specify the range of
-columns that the identifier will occupy, followed by an equals sign
-(@samp{=}) and the identifier variable name. The variable must already
-have been declared with @cmd{NUMERIC} or another command.
-
-@cmd{REPEATING DATA} should be the last command given within an
-@cmd{INPUT PROGRAM}. It should not be enclosed within a @cmd{LOOP}
-structure (@pxref{LOOP}). Use @cmd{DATA LIST} before, not after,
-@cmd{REPEATING DATA}.
-
-@node WRITE, , REPEATING DATA, Data Input and Output
-@section WRITE
-@vindex WRITE
-
-@display
-WRITE
- OUTFILE='filename'
- RECORDS=n_lines
- @{NOTABLE,TABLE@}
- /[line_no] arg@dots{}
-
-arg takes one of the following forms:
- 'string' [start-end]
- var_list start-end [type_spec]
- var_list (fortran_spec)
- var_list *
-@end display
-
-@code{WRITE} writes text or binary data to an output file.
-
-@xref{PRINT}, for more information on syntax and usage. The main
-difference between @code{PRINT} and @code{WRITE} is that @cmd{WRITE}
-uses write formats by default, where PRINT uses print formats.
-
-The sole additional difference is that if @cmd{WRITE} is used to send output
-to a binary file, carriage control characters will not be output.
-@xref{FILE HANDLE}, for information on how to declare a file as binary.
-
-@node System and Portable Files, Variable Attributes, Data Input and Output, Top
-@chapter System Files and Portable Files
-
-The commands in this chapter read, write, and examine system files and
-portable files.
-
-@menu
-* APPLY DICTIONARY:: Apply system file dictionary to active file.
-* EXPORT:: Write to a portable file.
-* GET:: Read from a system file.
-* IMPORT:: Read from a portable file.
-* MATCH FILES:: Merge system files.
-* SAVE:: Write to a system file.
-* SYSFILE INFO:: Display system file dictionary.
-* XSAVE:: Write to a system file, as a transform.
-@end menu
-
-@node APPLY DICTIONARY, EXPORT, System and Portable Files, System and Portable Files
-@section APPLY DICTIONARY
-@vindex APPLY DICTIONARY
-
-@display
-APPLY DICTIONARY FROM='filename'.
-@end display
-
-@cmd{APPLY DICTIONARY} applies the variable labels, value labels,
-and missing values from variables in a system file to corresponding
-variables in the active file. In some cases it also updates the
-weighting variable.
-
-Specify a system file with a file name string or as a file handle
-(@pxref{FILE HANDLE}). The dictionary in the system file will be read,
-but it will not replace the active file dictionary. The system file's
-data will not be read.
-
-Only variables with names that exist in both the active file and the
-system file are considered. Variables with the same name but different
-types (numeric, string) will cause an error message. Otherwise, the
-system file variables' attributes will replace those in their matching
-active file variables, as described below.
-
-If a system file variable has a variable label, then it will replace the
-active file variable's variable label. If the system file variable does
-not have a variable label, then the active file variable's variable
-label, if any, will be retained.
-
-If the active file variable is numeric or short string, then value
-labels and missing values, if any, will be copied to the active file
-variable. If the system file variable does not have value labels or
-missing values, then those in the active file variable, if any, will not
-be disturbed.
-
-Finally, weighting of the active file is updated (@pxref{WEIGHT}). If
-the active file has a weighting variable, and the system file does not,
-or if the weighting variable in the system file does not exist in the
-active file, then the active file weighting variable, if any, is
-retained. Otherwise, the weighting variable in the system file becomes
-the active file weighting variable.
-
-@cmd{APPLY DICTIONARY} takes effect immediately. It does not read the
-active
-file. The system file is not modified.
-
-@node EXPORT, GET, APPLY DICTIONARY, System and Portable Files
-@section EXPORT
-@vindex EXPORT
-
-@display
-EXPORT
- /OUTFILE='filename'
- /DROP=var_list
- /KEEP=var_list
- /RENAME=(src_names=target_names)@dots{}
-@end display
-
-The @cmd{EXPORT} procedure writes the active file dictionary and data to a
-specified portable file.
-
-The OUTFILE subcommand, which is the only required subcommand, specifies
-the portable file to be written as a file name string or a file handle
-(@pxref{FILE HANDLE}).
-
-DROP, KEEP, and RENAME follow the same format as the SAVE procedure
-(@pxref{SAVE}).
-
-@cmd{EXPORT} is a procedure. It causes the active file to be read.
-
-@node GET, IMPORT, EXPORT, System and Portable Files
-@section GET
-@vindex GET
-
-@display
-GET
- /FILE='filename'
- /DROP=var_list
- /KEEP=var_list
- /RENAME=(src_names=target_names)@dots{}
-@end display
-
-@cmd{GET} clears the current dictionary and active file and
-replaces them with the dictionary and data from a specified system file.
-
-The FILE subcommand is the only required subcommand. Specify the system
-file to be read as a string file name or a file handle (@pxref{FILE
-HANDLE}).
-
-By default, all the variables in a system file are read. The DROP
-subcommand can be used to specify a list of variables that are not to be
-read. By contrast, the KEEP subcommand can be used to specify variable
-that are to be read, with all other variables not read.
-
-Normally variables in a system file retain the names that they were
-saved under. Use the RENAME subcommand to change these names. Specify,
-within parentheses, a list of variable names followed by an equals sign
-(@samp{=}) and the names that they should be renamed to. Multiple
-parenthesized groups of variable names can be included on a single
-RENAME subcommand. Variables' names may be swapped using a RENAME
-subcommand of the form @samp{/RENAME=(A B=B A)}.
-
-Alternate syntax for the RENAME subcommand allows the parentheses to be
-eliminated. When this is done, only a single variable may be renamed at
-once. For instance, @samp{/RENAME=A=B}. This alternate syntax is
-deprecated.
-
-DROP, KEEP, and RENAME are performed in left-to-right order. They
-each may be present any number of times. @cmd{GET} never modifies a
-system file on disk. Only the active file read from the system file
-is affected by these subcommands.
-
-@cmd{GET} does not cause the data to be read, only the dictionary. The data
-is read later, when a procedure is executed.
-
-@node IMPORT, MATCH FILES, GET, System and Portable Files
-@section IMPORT
-@vindex IMPORT
-
-@display
-IMPORT
- /FILE='filename'
- /TYPE=@{COMM,TAPE@}
- /DROP=var_list
- /KEEP=var_list
- /RENAME=(src_names=target_names)@dots{}
-@end display
-
-The @cmd{IMPORT} transformation clears the active file dictionary and
-data and
-replaces them with a dictionary and data from a portable file on disk.
-
-The FILE subcommand, which is the only required subcommand, specifies
-the portable file to be read as a file name string or a file handle
-(@pxref{FILE HANDLE}).
-
-The TYPE subcommand is currently not used.
-
-DROP, KEEP, and RENAME follow the syntax used by @cmd{GET} (@pxref{GET}).
-
-@cmd{IMPORT} does not cause the data to be read, only the dictionary. The
-data is read later, when a procedure is executed.
-
-@node MATCH FILES, SAVE, IMPORT, System and Portable Files
-@section MATCH FILES
-@vindex MATCH FILES
-
-@display
-MATCH FILES
- /BY var_list
- /@{FILE,TABLE@}=@{*,'filename'@}
- /DROP=var_list
- /KEEP=var_list
- /RENAME=(src_names=target_names)@dots{}
- /IN=var_name
- /FIRST=var_name
- /LAST=var_name
- /MAP
-@end display
-
-@cmd{MATCH FILES} merges one or more system files, optionally
-including the active file. Records with the same values for BY
-variables are combined into a single record. Records with different
-values are output in order. Thus, multiple sorted system files are
-combined into a single sorted system file based on the value of the BY
-variables. The results of the merge become the new active file.
-
-The BY subcommand specifies a list of variables that are used to match
-records from each of the system files. Variables specified must exist
-in all the files specified on FILE and TABLE. BY should usually be
-specified. If TABLE is used then BY is required.
-
-Specify FILE with a system file as a file name string or file handle
-(@pxref{FILE HANDLE}), or with an asterisk (@samp{*}) to
-indicate the current active file. The files specified on FILE are
-merged together based on the BY variables, or combined case-by-case if
-BY is not specified. Normally at least two FILE subcommands should be
-specified.
-
-Specify TABLE with a system file to use it as a @dfn{table
-lookup file}. Records in table lookup files are not used up after
-they've been used once. This means that data in table lookup files can
-correspond to any number of records in FILE files. Table lookup files
-correspond to lookup tables in traditional relational database systems.
-It is incorrect to have records with duplicate BY values in table lookup
-files.
-
-Any number of FILE and TABLE subcommands may be specified. Each
-instance of FILE or TABLE can be followed by DROP, KEEP, and/or RENAME
-subcommands. These take the same form as the corresponding subcommands
-of @cmd{GET} (@pxref{GET}), and perform the same functions.
-
-Variables belonging to files that are not present for the current case
-are set to the system-missing value for numeric variables or spaces for
-string variables.
-
-IN, FIRST, LAST, and MAP are currently not used.
-
-@cmd{MATCH FILES} may not be specified following @cmd{TEMPORARY}
-(@pxref{TEMPORARY}) if the active file is used as an input source.
-
-@node SAVE, SYSFILE INFO, MATCH FILES, System and Portable Files
-@section SAVE
-@vindex SAVE
-
-@display
-SAVE
- /OUTFILE='filename'
- /@{COMPRESSED,UNCOMPRESSED@}
- /DROP=var_list
- /KEEP=var_list
- /RENAME=(src_names=target_names)@dots{}
-@end display
-
-The @cmd{SAVE} procedure causes the dictionary and data in the active
-file to
-be written to a system file.
-
-FILE is the only required subcommand. Specify the system
-file to be written as a string file name or a file handle (@pxref{FILE
-HANDLE}).
-
-The COMPRESS and UNCOMPRESS subcommand determine whether the saved
-system file is compressed. By default, system files are compressed.
-This default can be changed with the SET command (@pxref{SET}).
-
-By default, all the variables in the active file dictionary are written
-to the system file. The DROP subcommand can be used to specify a list
-of variables not to be written. In contrast, KEEP specifies variables
-to be written, with all variables not specified not written.
-
-Normally variables are saved to a system file under the same names they
-have in the active file. Use the RENAME subcommand to change these names.
-Specify, within parentheses, a list of variable names followed by an
-equals sign (@samp{=}) and the names that they should be renamed to.
-Multiple parenthesized groups of variable names can be included on a
-single RENAME subcommand. Variables' names may be swapped using a
-RENAME subcommand of the form @samp{/RENAME=(A B=B A)}.
-
-Alternate syntax for the RENAME subcommand allows the parentheses to be
-eliminated. When this is done, only a single variable may be renamed at
-once. For instance, @samp{/RENAME=A=B}. This alternate syntax is
-deprecated.
-
-DROP, KEEP, and RENAME are performed in left-to-right order. They
-each may be present any number of times. @cmd{SAVE} never modifies
-the active file. DROP, KEEP, and RENAME only affect the system file
-written to disk.
-
-@cmd{SAVE} causes the data to be read. It is a procedure.
-
-@node SYSFILE INFO, XSAVE, SAVE, System and Portable Files
-@section SYSFILE INFO
-@vindex SYSFILE INFO
-
-@display
-SYSFILE INFO FILE='filename'.
-@end display
-
-@cmd{SYSFILE INFO} reads the dictionary in a system file and
-displays the information in its dictionary.
-
-Specify a file name or file handle. @cmd{SYSFILE INFO} reads that file as
-a system file and displays information on its dictionary.
-
-@cmd{SYSFILE INFO} does not affect the current active file.
-
-@node XSAVE, , SYSFILE INFO, System and Portable Files
-@section XSAVE
-@vindex XSAVE
-
-@display
-XSAVE
- /FILE='filename'
- /@{COMPRESSED,UNCOMPRESSED@}
- /DROP=var_list
- /KEEP=var_list
- /RENAME=(src_names=target_names)@dots{}
-@end display
-
-The @cmd{XSAVE} transformation writes the active file dictionary and
-data to a
-system file stored on disk.
-
-@cmd{XSAVE} is a transformation, not a procedure. It is executed when the
-data is read by a procedure or procedure-like command. In all other
-respects, @cmd{XSAVE} is identical to @cmd{SAVE}. @xref{SAVE}, for
-more information
-on syntax and usage.
-
-@node Variable Attributes, Data Manipulation, System and Portable Files, Top
-@chapter Manipulating variables
-
-The variables in the active file dictionary are important. There are
-several utility functions for examining and adjusting them.
-
-@menu
-* ADD VALUE LABELS:: Add value labels to variables.
-* DISPLAY:: Display variable names & descriptions.
-* DISPLAY VECTORS:: Display a list of vectors.
-* FORMATS:: Set print and write formats.
-* LEAVE:: Don't clear variables between cases.
-* MISSING VALUES:: Set missing values for variables.
-* MODIFY VARS:: Rename, reorder, and drop variables.
-* NUMERIC:: Create new numeric variables.
-* PRINT FORMATS:: Set variable print formats.
-* RENAME VARIABLES:: Rename variables.
-* VALUE LABELS:: Set value labels for variables.
-* STRING:: Create new string variables.
-* VARIABLE LABELS:: Set variable labels for variables.
-* VECTOR:: Declare an array of variables.
-* WRITE FORMATS:: Set variable write formats.
-@end menu
-
-@node ADD VALUE LABELS, DISPLAY, Variable Attributes, Variable Attributes
-@section ADD VALUE LABELS
-@vindex ADD VALUE LABELS
-
-@display
-ADD VALUE LABELS
- /var_list value 'label' [value 'label']@dots{}
-@end display
-
-@cmd{ADD VALUE LABELS} has the same syntax and purpose as @cmd{VALUE
-LABELS} (@pxref{VALUE LABELS}), but it does not clear value
-labels from the variables before adding the ones specified.
-
-@node DISPLAY, DISPLAY VECTORS, ADD VALUE LABELS, Variable Attributes
-@section DISPLAY
-@vindex DISPLAY
-
-@display
-DISPLAY @{NAMES,INDEX,LABELS,VARIABLES,DICTIONARY,SCRATCH@}
- [SORTED] [var_list]
-@end display
-
-@cmd{DISPLAY} displays requested information on variables. Variables can
-optionally be sorted alphabetically. The entire dictionary or just
-specified variables can be described.
-
-One of the following keywords can be present:
-
-@table @asis
-@item NAMES
-The variables' names are displayed.
-
-@item INDEX
-The variables' names are displayed along with a value describing their
-position within the active file dictionary.
-
-@item LABELS
-Variable names, positions, and variable labels are displayed.
-
-@item VARIABLES
-Variable names, positions, print and write formats, and missing values
-are displayed.
-
-@item DICTIONARY
-Variable names, positions, print and write formats, missing values,
-variable labels, and value labels are displayed.
-
-@item SCRATCH
-Varible names are displayed, for scratch variables only (@pxref{Scratch
-Variables}).
-@end table
-
-If SORTED is specified, then the variables are displayed in ascending
-order based on their names; otherwise, they are displayed in the order
-that they occur in the active file dictionary.
-
-@node DISPLAY VECTORS, FORMATS, DISPLAY, Variable Attributes
-@section DISPLAY VECTORS
-@vindex DISPLAY VECTORS
-
-@display
-DISPLAY VECTORS.
-@end display
-
-@cmd{DISPLAY VECTORS} lists all the currently declared vectors.
-
-@node FORMATS, LEAVE, DISPLAY VECTORS, Variable Attributes
-@section FORMATS
-@vindex FORMATS
-
-@display
-FORMATS var_list (fmt_spec).
-@end display
-
-@cmd{FORMATS} set both print and write formats for the specified
-variables to the specified format specification. @xref{Input/Output
-Formats}.
-
-Specify a list of variables followed by a format specification in
-parentheses. The print and write formats of the specified variables
-will be changed.
-
-Additional lists of variables and formats may be included if they are
-delimited by a slash (@samp{/}).
-
-@cmd{FORMATS} takes effect immediately. It is not affected by
-conditional and looping structures such as @cmd{DO IF} or @cmd{LOOP}.
-
-@node LEAVE, MISSING VALUES, FORMATS, Variable Attributes
-@section LEAVE
-@vindex LEAVE
-
-@display
-LEAVE var_list.
-@end display
-
-@cmd{LEAVE} prevents the specified variables from being
-reinitialized whenever a new case is processed.
-
-Normally, when a data file is processed, every variable in the active
-file is initialized to the system-missing value or spaces at the
-beginning of processing for each case. When a variable has been
-specified on @cmd{LEAVE}, this is not the case. Instead, that variable is
-initialized to 0 (not system-missing) or spaces for the first case.
-After that, it retains its value between cases.
-
-This becomes useful for counters. For instance, in the example below
-the variable SUM maintains a running total of the values in the ITEM
-variable.
-
-@example
-DATA LIST /ITEM 1-3.
-COMPUTE SUM=SUM+ITEM.
-PRINT /ITEM SUM.
-LEAVE SUM
-BEGIN DATA.
-123
-404
-555
-999
-END DATA.
-@end example
-
-@noindent Partial output from this example:
-
-@example
-123 123.00
-404 527.00
-555 1082.00
-999 2081.00
-@end example
-
-It is best to use @cmd{LEAVE} command immediately before invoking a
-procedure command, because the left status of variables is reset by
-certain transformations---for instance, @cmd{COMPUTE} and @cmd{IF}.
-Left status is also reset by all procedure invocations.
-
-@node MISSING VALUES, MODIFY VARS, LEAVE, Variable Attributes
-@section MISSING VALUES
-@vindex MISSING VALUES
-
-@display
-MISSING VALUES var_list (missing_values).
-
-missing_values takes one of the following forms:
- num1
- num1, num2
- num1, num2, num3
- num1 THRU num2
- num1 THRU num2, num3
- string1
- string1, string2
- string1, string2, string3
-As part of a range, LO or LOWEST may take the place of num1;
-HI or HIGHEST may take the place of num2.
-@end display
-
-@cmd{MISSING VALUES} sets user-missing values for numeric and
-short string variables. Long string variables may not have missing
-values.
-
-Specify a list of variables, followed by a list of their user-missing
-values in parentheses. Up to three discrete values may be given, or,
-for numeric variables only, a range of values optionally accompanied by
-a single discrete value. Ranges may be open-ended on one end, indicated
-through the use of the keyword LO or LOWEST or HI or HIGHEST.
-
-The @cmd{MISSING VALUES} command takes effect immediately. It is not
-affected by conditional and looping constructs such as @cmd{DO IF} or
-@cmd{LOOP}.
-
-@node MODIFY VARS, NUMERIC, MISSING VALUES, Variable Attributes
-@section MODIFY VARS
-@vindex MODIFY VARS
-
-@display
-MODIFY VARS
- /REORDER=@{FORWARD,BACKWARD@} @{POSITIONAL,ALPHA@} (var_list)@dots{}
- /RENAME=(old_names=new_names)@dots{}
- /@{DROP,KEEP@}=var_list
- /MAP
-@end display
-
-@cmd{MODIFY VARS} reorders, renames, and deletes variables in the
-active file.
-
-At least one subcommand must be specified, and no subcommand may be
-specified more than once. DROP and KEEP may not both be specified.
-
-The REORDER subcommand changes the order of variables in the active
-file. Specify one or more lists of variable names in parentheses. By
-default, each list of variables is rearranged into the specified order.
-To put the variables into the reverse of the specified order, put
-keyword BACKWARD before the parentheses. To put them into alphabetical
-order in the dictionary, specify keyword ALPHA before the parentheses.
-BACKWARD and ALPHA may also be combined.
-
-To rename variables in the active file, specify RENAME, an equals sign
-(@samp{=}), and lists of the old variable names and new variable names
-separated by another equals sign within parentheses. There must be the
-same number of old and new variable names. Each old variable is renamed to
-the corresponding new variable name. Multiple parenthesized groups of
-variables may be specified.
-
-The DROP subcommand deletes a specified list of variables from the
-active file.
-
-The KEEP subcommand keeps the specified list of variables in the active
-file. Any unlisted variables are deleted from the active file.
-
-MAP is currently ignored.
-
-If either DROP or KEEP is specified, the data is read; otherwise it is
-not.
-
-@cmd{MODIFY VARS} may not be specified following @cmd{TEMPORARY}
-(@pxref{TEMPORARY}).
-
-@node NUMERIC, PRINT FORMATS, MODIFY VARS, Variable Attributes
-@section NUMERIC
-@vindex NUMERIC
-
-@display
-NUMERIC /var_list [(fmt_spec)].
-@end display
-
-@cmd{NUMERIC} explicitly declares new numeric variables, optionally
-setting their output formats.
-
-Specify a slash (@samp{/}), followed by the names of the new numeric
-variables. If you wish to set their output formats, follow their names
-by an output format specification in parentheses (@pxref{Input/Output
-Formats}); otherwise, the default is F8.2.
-
-Variables created with @cmd{NUMERIC} are initialized to the
-system-missing value.
-
-@node PRINT FORMATS, RENAME VARIABLES, NUMERIC, Variable Attributes
-@section PRINT FORMATS
-@vindex PRINT FORMATS
-
-@display
-PRINT FORMATS var_list (fmt_spec).
-@end display
-
-@cmd{PRINT FORMATS} sets the print formats for the specified
-variables to the specified format specification.
-
-Its syntax is identical to that of @cmd{FORMATS} (@pxref{FORMATS}),
-but @cmd{PRINT FORMATS} sets only print formats, not write formats.
-
-@node RENAME VARIABLES, VALUE LABELS, PRINT FORMATS, Variable Attributes
-@section RENAME VARIABLES
-@vindex RENAME VARIABLES
-
-@display
-RENAME VARIABLES (old_names=new_names)@dots{} .
-@end display
-
-@cmd{RENAME VARIABLES} changes the names of variables in the active
-file. Specify lists of the old variable names and new
-variable names, separated by an equals sign (@samp{=}), within
-parentheses. There must be the same number of old and new variable
-names. Each old variable is renamed to the corresponding new variable
-name. Multiple parenthesized groups of variables may be specified.
-
-@cmd{RENAME VARIABLES} takes effect immediately. It does not cause the data
-to be read.
-
-@cmd{RENAME VARIABLES} may not be specified following @cmd{TEMPORARY}
-(@pxref{TEMPORARY}).
-
-@node VALUE LABELS, STRING, RENAME VARIABLES, Variable Attributes
-@section VALUE LABELS
-@vindex VALUE LABELS
-
-@display
-VALUE LABELS
- /var_list value 'label' [value 'label']@dots{}
-@end display
-
-@cmd{VALUE LABELS} allows values of numeric and short string
-variables to be associated with labels. In this way, a short value can
-stand for a long value.
-
-To set up value labels for a set of variables, specify the
-variable names after a slash (@samp{/}), followed by a list of values
-and their associated labels, separated by spaces. Long string
-variables may not be specified.
-
-Before @cmd{VALUE LABELS} is executed, any existing value labels
-are cleared from the variables specified. Use @cmd{ADD VALUE LABELS}
-(@pxref{ADD VALUE LABELS}) to add value labels without clearing those
-already present.
-
-@node STRING, VARIABLE LABELS, VALUE LABELS, Variable Attributes
-@section STRING
-@vindex STRING
-
-@display
-STRING /var_list (fmt_spec).
-@end display
-
-@cmd{STRING} creates new string variables for use in
-transformations.
-
-Specify a slash (@samp{/}), followed by the names of the string
-variables to create and the desired output format specification in
-parentheses (@pxref{Input/Output Formats}). Variable widths are
-implicitly derived from the specified output formats.
-
-Created variables are initialized to spaces.
-
-@node VARIABLE LABELS, VECTOR, STRING, Variable Attributes
-@section VARIABLE LABELS
-@vindex VARIABLE LABELS
-
-@display
-VARIABLE LABELS
- /var_list 'var_label'.
-@end display
-
-@cmd{VARIABLE LABELS} associates explanatory names
-with variables. This name, called a @dfn{variable label}, is displayed by
-statistical procedures.
-
-To assign a variable label to a group of variables, specify a slash
-(@samp{/}), followed by the list of variable names and the variable
-label as a string.
-
-@node VECTOR, WRITE FORMATS, VARIABLE LABELS, Variable Attributes
-@section VECTOR
-@vindex VECTOR
-
-@display
-Two possible syntaxes:
- VECTOR vec_name=var_list.
- VECTOR vec_name_list(count).
-@end display
-
-@cmd{VECTOR} allows a group of variables to be accessed as if they
-were consecutive members of an array with a vector(index) notation.
-
-To make a vector out of a set of existing variables, specify a name for
-the vector followed by an equals sign (@samp{=}) and the variables that
-belong in the vector.
-
-To make a vector and create variables at the same time, specify one or
-more vector names followed by a count in parentheses. This will cause
-variables named @code{@var{vec}1} through @code{@var{vec}@var{count}}
-to be created as numeric variables with print and write format F8.2.
-Variable names including numeric suffixes may not exceed 8 characters
-in length, and none of the variables may exist prior to @cmd{VECTOR}.
-
-All the variables in a vector must be the same type.
-
-Vectors created with @cmd{VECTOR} disappear after any procedure or
-procedure-like command is executed. The variables contained in the
-vectors remain, unless they are scratch variables (@pxref{Scratch
-Variables}).
-
-Variables within a vector may be references in expressions using
-@code{vector(index)} syntax.
-
-@node WRITE FORMATS, , VECTOR, Variable Attributes
-@section WRITE FORMATS
-@vindex WRITE FORMATS
-
-@display
-WRITE FORMATS var_list (fmt_spec).
-@end display
-
-@cmd{WRITE FORMATS} sets the write formats for the specified variables
-to the specified format specification. Its syntax is identical to
-that of FORMATS (@pxref{FORMATS}), but @cmd{WRITE FORMATS} sets only
-write formats, not print formats.
-
-@node Data Manipulation, Data Selection, Variable Attributes, Top
-@chapter Data transformations
-@cindex transformations
-
-The PSPP procedures examined in this chapter manipulate data and
-prepare the active file for later analyses. They do not produce output,
-as a rule.
-
-@menu
-* AGGREGATE:: Summarize multiple cases into a single case.
-* AUTORECODE:: Automatic recoding of variables.
-* COMPUTE:: Assigning a variable a calculated value.
-* COUNT:: Counting variables with particular values.
-* FLIP:: Exchange variables with cases.
-* IF:: Conditionally assigning a calculated value.
-* RECODE:: Mapping values from one set to another.
-* SORT CASES:: Sort the active file.
-@end menu
-
-@node AGGREGATE, AUTORECODE, Data Manipulation, Data Manipulation
-@section AGGREGATE
-@vindex AGGREGATE
-
-@display
-AGGREGATE
- /BREAK=var_list
- /PRESORTED
- /OUTFILE=@{*,'filename'@}
- /DOCUMENT
- /MISSING=COLUMNWISE
- /dest_vars=agr_func(src_vars, args@dots{})@dots{}
-@end display
-
-@cmd{AGGREGATE} summarizes groups of cases into single cases.
-Cases are divided into groups that have the same values for one or more
-variables called @dfn{break variables}. Several functions are available
-for summarizing case contents.
-
-At least one break variable must be specified on BREAK, the only
-required subcommand. The values of these variables are used to divide
-the active file into groups to be summarized. In addition, at least
-one @var{dest_var} must be specified.
-
-By default, the active file is sorted based on the break variables
-before aggregation takes place. If the active file is already sorted
-or otherwise grouped in terms of the break variables, specify
-PRESORTED to save time.
-
-The OUTFILE subcommand specifies a system file by file name string or
-file handle (@pxref{FILE HANDLE}). The aggregated cases are written to
-this file. If OUTFILE is not specified, or if @samp{*} is specified,
-then the aggregated cases replace the active file.
-
-Specify DOCUMENT to copy the documents from the active file into the
-aggregate file (@pxref{DOCUMENT}). Otherwise, the aggregate file will
-not contain any documents, even if the aggregate file replaces the
-active file.
-
-One or more sets of aggregation variables must be specified. Each set
-comprises a list of aggregation variables, an equals sign (@samp{=}),
-the name of an aggregation function (see the list below), and a list
-of source variables in parentheses. Some aggregation functions expect
-additional arguments following the source variable names.
-
-Each set must have exactly as many source variables as aggregation
-variables. Each aggregation variable receives the results of applying
-the specified aggregation function to the corresponding source
-variable. Most aggregation functions may be applied to numeric and
-short and long string variables. Others, marked below, are restricted
-to numeric values.
-
-The available aggregation functions are as follows:
-
-@table @asis
-@item SUM(var_name)
-Sum. Limited to numeric values.
-@item MEAN(var_name)
-Arithmetic mean. Limited to numeric values.
-@item SD(var_name)
-Standard deviation of the mean. Limited to numeric values.
-@item MAX(var_name)
-Maximum value.
-@item MIN(var_name)
-Minimum value.
-@item FGT(var_name, value)
-@itemx PGT(var_name, value)
-Fraction between 0 and 1, or percentage between 0 and 100, respectively,
-of values greater than the specified constant.
-@item FLT(var_name, value)
-@itemx PLT(var_name, value)
-Fraction or percentage, respectively, of values less than the specified
-constant.
-@item FIN(var_name, low, high)
-@itemx PIN(var_name, low, high)
-Fraction or percentage, respectively, of values within the specified
-inclusive range of constants.
-@item FOUT(var_name, low, high)
-@itemx POUT(var_name, low, high)
-Fraction or percentage, respectively, of values strictly outside the
-specified range of constants.
-@item N(var_name)
-Number of non-missing values.
-@item N
-Number of cases aggregated to form this group. Don't supply a source
-variable for this aggregation function.
-@item NU(var_name)
-Number of non-missing values. Each case is considered to have a weight
-of 1, regardless of the current weighting variable (@pxref{WEIGHT}).
-@item NU
-Number of cases aggregated to form this group. Each case is considered
-to have a weight of 1, regardless of the current weighting variable.
-@item NMISS(var_name)
-Number of missing values.
-@item NUMISS(var_name)
-Number of missing values. Each case is considered to have a weight of
-1, regardless of the current weighting variable.
-@item FIRST(var_name)
-First value in this group.
-@item LAST(var_name)
-Last value in this group.
-@end table
-
-Aggregation functions compare string values in terms of internal
-character codes. On most modern computers, this is a form of ASCII.
-
-The aggregation functions listed above exclude all user-missing values
-from calculations. To include user-missing values, insert a period
-(@samp{.}) between the function name and left parenthesis
-(e.g.@: @samp{SUM.}).
-
-Normally, only a single case (for SD and SD., two cases) need be
-non-missing in each group for the aggregate variable to be
-non-missing. Specifying /MISSING=COLUMNWISE inverts this behavior, so
-that the aggregate variable becomes missing if any aggregated value is
-missing.
-
-@cmd{AGGREGATE} both ignores and cancels the current @cmd{SPLIT FILE}
-settings (@pxref{SPLIT FILE}).
-
-@node AUTORECODE, COMPUTE, AGGREGATE, Data Manipulation
-@section AUTORECODE
-@vindex AUTORECODE
-
-@display
-AUTORECODE VARIABLES=src_vars INTO dest_vars
- /DESCENDING
- /PRINT
-@end display
-
-The @cmd{AUTORECODE} procedure considers the @var{n} values that a variable
-takes on and maps them onto values 1@dots{}@var{n} on a new numeric
-variable.
-
-Subcommand VARIABLES is the only required subcommand and must come
-first. Specify VARIABLES, an equals sign (@samp{=}), a list of source
-variables, INTO, and a list of target variables. There must the same
-number of source and target variables. The target variables must not
-already exist.
-
-By default, increasing values of a source variable (for a string, this
-is based on character code comparisons) are recoded to increasing values
-of its target variable. To cause increasing values of a source variable
-to be recoded to decreasing values of its target variable (@var{n} down
-to 1), specify DESCENDING.
-
-PRINT is currently ignored.
-
-@cmd{AUTORECODE} is a procedure. It causes the data to be read.
-
-@node COMPUTE, COUNT, AUTORECODE, Data Manipulation
-@section COMPUTE
-@vindex COMPUTE
-
-@display
-COMPUTE variable = expression.
- or
-COMPUTE vector(index) = expression.
-@end display
-
-@cmd{COMPUTE} assigns the value of an expression to a target
-variable. For each case, the expression is evaluated and its value
-assigned to the target variable. Numeric and short and long string
-variables may be assigned. When a string expression's width differs
-from the target variable's width, the string result of the expression
-is truncated or padded with spaces on the right as necessary. The
-expression and variable types must match.
-
-For numeric variables only, the target variable need not already
-exist. Numeric variables created by @cmd{COMPUTE} are assigned an
-@code{F8.2} output format. String variables must be declared before
-they can be used as targets for @cmd{COMPUTE}.
-
-The target variable may be specified as an element of a vector
-(@pxref{VECTOR}). In this case, a vector index expression must be
-specified in parentheses following the vector name. The index
-expression must evaluate to a numeric value that, after rounding down
-to the nearest integer, is a valid index for the named vector.
-
-Using @cmd{COMPUTE} to assign to a variable specified on @cmd{LEAVE}
-(@pxref{LEAVE}) resets the variable's left state. Therefore,
-@code{LEAVE} should be specified following @cmd{COMPUTE}, not before.
-
-@cmd{COMPUTE} is a transformation. It does not cause the active file to be
-read.
-
-When @cmd{COMPUTE} is specified following @cmd{TEMPORARY}
-(@pxref{TEMPORARY}), the @cmd{LAG} function may not be used
-(@pxref{LAG}).
-
-@node COUNT, FLIP, COMPUTE, Data Manipulation
-@section COUNT
-@vindex COUNT
-
-@display
-COUNT var_name = var@dots{} (value@dots{}).
-
-Each value takes one of the following forms:
- number
- string
- num1 THRU num2
- MISSING
- SYSMIS
-In addition, num1 and num2 can be LO or LOWEST, or HI or HIGHEST,
-respectively.
-@end display
-
-@cmd{COUNT} creates or replaces a numeric @dfn{target} variable that
-counts the occurrence of a @dfn{criterion} value or set of values over
-one or more @dfn{test} variables for each case.
-
-The target variable values are always nonnegative integers. They are
-never missing. The target variable is assigned an F8.2 output format.
-@xref{Input/Output Formats}. Any variables, including long and short
-string variables, may be test variables.
-
-User-missing values of test variables are treated just like any other
-values. They are @strong{not} treated as system-missing values.
-User-missing values that are criterion values or inside ranges of
-criterion values are counted as any other values. However (for numeric
-variables), keyword MISSING may be used to refer to all system-
-and user-missing values.
-
-@cmd{COUNT} target variables are assigned values in the order
-specified. In the command @code{COUNT A=A B(1) /B=A B(2).}, the
-following actions occur:
-
-@itemize @minus
-@item
-The number of occurrences of 1 between @code{A} and @code{B} is counted.
-
-@item
-@code{A} is assigned this value.
-
-@item
-The number of occurrences of 1 between @code{B} and the @strong{new}
-value of @code{A} is counted.
-
-@item
-@code{B} is assigned this value.
-@end itemize
-
-Despite this ordering, all @cmd{COUNT} criterion variables must exist
-before the procedure is executed---they may not be created as target
-variables earlier in the command! Break such a command into two
-separate commands.
-
-The examples below may help to clarify.
-
-@enumerate A
-@item
-Assuming @code{Q0}, @code{Q2}, @dots{}, @code{Q9} are numeric variables,
-the following commands:
-
-@enumerate
-@item
-Count the number of times the value 1 occurs through these variables
-for each case and assigns the count to variable @code{QCOUNT}.
-
-@item
-Print out the total number of times the value 1 occurs throughout
-@emph{all} cases using @cmd{DESCRIPTIVES}. @xref{DESCRIPTIVES}, for
-details.
-@end enumerate
-
-@example
-COUNT QCOUNT=Q0 TO Q9(1).
-DESCRIPTIVES QCOUNT /STATISTICS=SUM.
-@end example
-
-@item
-Given these same variables, the following commands:
-
-@enumerate
-@item
-Count the number of valid values of these variables for each case and
-assigns the count to variable @code{QVALID}.
-
-@item
-Multiplies each value of @code{QVALID} by 10 to obtain a percentage of
-valid values, using @cmd{COMPUTE}. @xref{COMPUTE}, for details.
-
-@item
-Print out the percentage of valid values across all cases, using
-@cmd{DESCRIPTIVES}. @xref{DESCRIPTIVES}, for details.
-@end enumerate
-
-@example
-COUNT QVALID=Q0 TO Q9 (LO THRU HI).
-COMPUTE QVALID=QVALID*10.
-DESCRIPTIVES QVALID /STATISTICS=MEAN.
-@end example
-@end enumerate
-
-@node FLIP, IF, COUNT, Data Manipulation
-@section FLIP
-@vindex FLIP
-
-@display
-FLIP /VARIABLES=var_list /NEWNAMES=var_name.
-@end display
-
-@cmd{FLIP} transposes rows and columns in the active file. It
-causes cases to be swapped with variables, and vice versa.
-
-All variables in the transposed active file are numeric. String
-variables take on the system-missing value in the transposed file.
-
-No subcommands are required. The VARIABLES subcommand specifies
-variables that will be transformed into cases. Variables not specified
-are discarded. By default, all variables are selected for
-transposition.
-
-The variables specified by NEWNAMES, which must be a string variable, is
-used to give names to the variables created by @cmd{FLIP}. If
-NEWNAMES is not
-specified then the default is a variable named CASE_LBL, if it exists.
-If it does not then the variables created by FLIP are named VAR000
-through VAR999, then VAR1000, VAR1001, and so on.
-
-When a NEWNAMES variable is available, the names must be canonicalized
-before becoming variable names. Invalid characters are replaced by
-letter @samp{V} in the first position, or by @samp{_} in subsequent
-positions. If the name thus generated is not unique, then numeric
-extensions are added, starting with 1, until a unique name is found or
-there are no remaining possibilities. If the latter occurs then the
-FLIP operation aborts.
-
-The resultant dictionary contains a CASE_LBL variable, which stores the
-names of the variables in the dictionary before the transposition. If
-the active file is subsequently transposed using @cmd{FLIP}, this
-variable can
-be used to recreate the original variable names.
-
-FLIP honors N OF CASES. It ignores TEMPORARY, so that ``temporary''
-transformations become permanent.
-
-@node IF, RECODE, FLIP, Data Manipulation
-@section IF
-@vindex IF
-
-@display
-IF condition variable=expression.
- or
-IF condition vector(index)=expression.
-@end display
-
-The @cmd{IF} transformation conditionally assigns the value of a target
-expression to a target variable, based on the truth of a test
-expression.
-
-Specify a boolean-valued expression (@pxref{Expressions}) to be tested
-following the IF keyword. This expression is evaluated for each case.
-If the value is true, then the value of the expression is computed and
-assigned to the specified variable. If the value is false or missing,
-nothing is done. Numeric and short and long string variables may be
-assigned. When a string expression's width differs from the target
-variable's width, the string result of the expression is truncated or
-padded with spaces on the right as necessary. The expression and
-variable types must match.
-
-The target variable may be specified as an element of a vector
-(@pxref{VECTOR}). In this case, a vector index expression must be
-specified in parentheses following the vector name. The index
-expression must evaluate to a numeric value that, after rounding down
-to the nearest integer, is a valid index for the named vector.
-
-Using @cmd{IF} to assign to a variable specified on @cmd{LEAVE}
-(@pxref{LEAVE}) resets the variable's left state. Therefore,
-@code{LEAVE} should be specified following @cmd{IF}, not before.
-
-When @cmd{IF} is specified following @cmd{TEMPORARY}
-(@pxref{TEMPORARY}), the @cmd{LAG} function may not be used
-(@pxref{LAG}).
-
-@node RECODE, SORT CASES, IF, Data Manipulation
-@section RECODE
-@vindex RECODE
-
-@display
-RECODE var_list (src_value@dots{}=dest_value)@dots{} [INTO var_list].
-
-src_value may take the following forms:
- number
- string
- num1 THRU num2
- MISSING
- SYSMIS
- ELSE
-Open-ended ranges may be specified using LO or LOWEST for num1
-or HI or HIGHEST for num2.
-
-dest_value may take the following forms:
- num
- string
- SYSMIS
- COPY
-@end display
-
-@cmd{RECODE} translates data from one range of values to
-another, via flexible user-specified mappings. Data may be remapped
-in-place or copied to new variables. Numeric, short string, and long
-string data can be recoded.
-
-Specify the list of source variables, followed by one or more mapping
-specifications each enclosed in parentheses. If the data is to be
-copied to new variables, specify INTO, then the list of target
-variables. String target variables must already have been declared
-using @cmd{STRING} or another transformation, but numeric target
-variables can
-be created on the fly. There must be exactly as many target variables
-as source variables. Each source variable is remapped into its
-corresponding target variable.
-
-When INTO is not used, the input and output variables must be of the
-same type. Otherwise, string values can be recoded into numeric values,
-and vice versa. When this is done and there is no mapping for a
-particular value, either a value consisting of all spaces or the
-system-missing value is assigned, depending on variable type.
-
-Mappings are considered from left to right. The first src_value that
-matches the value of the source variable causes the target variable to
-receive the value indicated by the dest_value. Literal number, string,
-and range src_value's should be self-explanatory. MISSING as a
-src_value matches any user- or system-missing value. SYSMIS matches the
-system missing value only. ELSE is a catch-all that matches anything.
-It should be the last src_value specified.
-
-Numeric and string dest_value's should also be self-explanatory. COPY
-causes the input values to be copied to the output. This is only value
-if the source and target variables are of the same type. SYSMIS
-indicates the system-missing value.
-
-If the source variables are strings and the target variables are
-numeric, then there is one additional mapping available: (CONVERT),
-which must be the last specified mapping. CONVERT causes a number
-specified as a string to be converted to a numeric value. If the string
-cannot be parsed as a number, then the system-missing value is assigned.
-
-Multiple recodings can be specified on a single @cmd{RECODE} invocation.
-Introduce additional recodings with a slash (@samp{/}) to
-separate them from the previous recodings.
-
-@node SORT CASES, , RECODE, Data Manipulation
-@section SORT CASES
-@vindex SORT CASES
-
-@display
-SORT CASES BY var_list.
-@end display
-
-@cmd{SORT CASES} sorts the active file by the values of one or more
-variables.
-
-Specify BY and a list of variables to sort by. By default, variables
-are sorted in ascending order. To override sort order, specify (D) or
-(DOWN) after a list of variables to get descending order, or (A) or (UP)
-for ascending order. These apply to the entire list of variables
-preceding them.
-
-@cmd{SORT CASES} is a procedure. It causes the data to be read.
-
-@cmd{SORT CASES} attempts to sort the entire active file in main memory.
-If main memory is exhausted, it falls back to a merge sort algorithm that
-involves writing and reading numerous temporary files.
-
-@cmd{SORT CASES} may not be specified following TEMPORARY.
-
-@node Data Selection, Conditionals and Looping, Data Manipulation, Top
-@chapter Selecting data for analysis
-
-This chapter documents PSPP commands that temporarily or permanently
-select data records from the active file for analysis.
-
-@menu
-* FILTER:: Exclude cases based on a variable.
-* N OF CASES:: Limit the size of the active file.
-* PROCESS IF:: Temporarily excluding cases.
-* SAMPLE:: Select a specified proportion of cases.
-* SELECT IF:: Permanently delete selected cases.
-* SPLIT FILE:: Do multiple analyses with one command.
-* TEMPORARY:: Make transformations' effects temporary.
-* WEIGHT:: Weight cases by a variable.
-@end menu
-
-@node FILTER, N OF CASES, Data Selection, Data Selection
-@section FILTER
-@vindex FILTER
-
-@display
-FILTER BY var_name.
-FILTER OFF.
-@end display
-
-@cmd{FILTER} allows a boolean-valued variable to be used to select
-cases from the data stream for processing.
-
-To set up filtering, specify BY and a variable name. Keyword
-BY is optional but recommended. Cases which have a zero or system- or
-user-missing value are excluded from analysis, but not deleted from the
-data stream. Cases with other values are analyzed.
-To filter based on a different condition, use
-transformations such as @cmd{COMPUTE} or @cmd{RECODE} to compute a
-filter variable of the required form, then specify that variable on
-@cmd{FILTER}.
-
-@code{FILTER OFF} turns off case filtering.
-
-Filtering takes place immediately before cases pass to a procedure for
-analysis. Only one filter variable may be active at a time. Normally,
-case filtering continues until it is explicitly turned off with @code{FILTER
-OFF}. However, if @cmd{FILTER} is placed after TEMPORARY, it filters only
-the next procedure or procedure-like command.
-
-@node N OF CASES, PROCESS IF, FILTER, Data Selection
-@section N OF CASES
-@vindex N OF CASES
-
-@display
-N [OF CASES] num_of_cases [ESTIMATED].
-@end display
-
-Sometimes you may want to disregard cases of your input. @cmd{N} can
-do this. @code{N 100} tells PSPP to disregard all cases after the
-first 100.
-
-If the value specified for @cmd{N} is greater than the number of cases
-read in, the value is ignored.
-
-@cmd{N} does not discard cases or prevent them from being read. It
-just causes cases beyond the last one specified to be ignored by data
-analysis commands.
-
-A later @cmd{N} command can increase or decrease the number of cases
-selected. (To select all the cases without knowing how many there are,
-specify a very high number: 100000 or whatever you think is large enough.)
-
-Transformation procedures performed after @cmd{N} is executed
-@emph{do} cause cases to be discarded.
-
-@cmd{SAMPLE}, @cmd{PROCESS IF}, and @cmd{SELECT IF} have
-precedence over @cmd{N}---the same results are obtained by both of the
-following fragments, given the same random number seeds:
-
-@example
-@i{@dots{}set up, read in data@dots{}}
-N 100.
-SAMPLE .5.
-@i{@dots{}analyze data@dots{}}
-
-@i{@dots{}set up, read in data@dots{}}
-SAMPLE .5.
-N 100.
-@i{@dots{}analyze data@dots{}}
-@end example
-
-Both fragments above first randomly sample approximately half of the
-cases, then select the first 100 of those sampled.
-
-@cmd{N} with the @code{ESTIMATED} keyword gives an
-estimated number of cases before @cmd{DATA LIST} or another command to
-read in data. @code{ESTIMATED} never limits the number of cases
-processed by procedures. PSPP currently does not make use of
-case count estimates.
-
-When @cmd{N} is specified after @cmd{TEMPORARY}, it affects only
-the next procedure (@pxref{TEMPORARY}).
-
-@node PROCESS IF, SAMPLE, N OF CASES, Data Selection
-@section PROCESS IF
-@vindex PROCESS IF
-
-@example
-PROCESS IF expression.
-@end example
-
-@cmd{PROCESS IF} temporarily eliminates cases from the
-data stream. Its effects are active only through the execution of the
-next procedure or procedure-like command.
-
-Specify a boolean expression (@pxref{Expressions}). If the value of the
-expression is true for a particular case, the case will be analyzed. If
-the expression has a false or missing value, then the case will be
-deleted from the data stream for this procedure only.
-
-Regardless of its placement relative to other commands, @cmd{PROCESS IF}
-always takes effect immediately before data passes to the procedure.
-Only one @cmd{PROCESS IF} command may be in effect at any given time.
-
-The effects of @cmd{PROCESS IF} are similar, but not identical, to the
-effects of executing @cmd{TEMPORARY}, then @cmd{SELECT IF}
-(@pxref{SELECT IF}).
-
-The filtering performed by @cmd{PROCESS IF} takes place immediately
-before cases pass to a procedure for analysis. Because @cmd{PROCESS
-IF} affects only a single procedure, its placement relative to
-@cmd{TEMPORARY} is unimportant.
-
-@cmd{PROCESS IF} is deprecated. It is included for compatibility with
-old command files. New syntax files should use @cmd{SELECT IF} or
-@cmd{FILTER} instead.
-
-@node SAMPLE, SELECT IF, PROCESS IF, Data Selection
-@section SAMPLE
-@vindex SAMPLE
-
-@display
-SAMPLE num1 [FROM num2].
-@end display
-
-@cmd{SAMPLE} randomly samples a proportion of the cases in the active
-file. Unless it follows @cmd{TEMPORARY}, it operates as a
-transformation, permanently removing cases from the active file.
-
-The proportion to sample can be expressed as a single number between 0
-and 1. If @code{k} is the number specified, and @code{N} is the number
-of currently-selected cases in the active file, then after
-@code{SAMPLE @var{k}.}, approximately @code{k*N} cases will be
-selected.
-
-The proportion to sample can also be specified in the style @code{SAMPLE
-@var{m} FROM @var{N}}. With this style, cases are selected as follows:
-
-@enumerate
-@item
-If @var{N} is equal to the number of currently-selected cases in the
-active file, exactly @var{m} cases will be selected.
-
-@item
-If @var{N} is greater than the number of currently-selected cases in the
-active file, an equivalent proportion of cases will be selected.
-
-@item
-If @var{N} is less than the number of currently-selected cases in the
-active, exactly @var{m} cases will be selected @emph{from the first
-@var{N} cases in the active file.}
-@end enumerate
-
-@cmd{SAMPLE} and @cmd{SELECT IF} are performed in
-the order specified by the syntax file.
-
-@cmd{SAMPLE} is always performed before @code{N OF CASES}, regardless
-of ordering in the syntax file (@pxref{N OF CASES}).
-
-The same values for @cmd{SAMPLE} may result in different samples. To
-obtain the same sample, use the @code{SET} command to set the random
-number seed to the same value before each @cmd{SAMPLE}. Different
-samples may still result when the file is processed on systems with
-differing endianness or floating-point formats. By default, the
-random number seed is based on the system time.
-
-@node SELECT IF, SPLIT FILE, SAMPLE, Data Selection
-@section SELECT IF
-@vindex SELECT IF
-
-@display
-SELECT IF expression.
-@end display
-
-@cmd{SELECT IF} selects cases for analysis based on the value of a
-boolean expression. Cases not selected are permanently eliminated
-from the active file, unless @cmd{TEMPORARY} is in effect
-(@pxref{TEMPORARY}).
-
-Specify a boolean expression (@pxref{Expressions}). If the value of the
-expression is true for a particular case, the case will be analyzed. If
-the expression has a false or missing value, then the case will be
-deleted from the data stream.
-
-Place @cmd{SELECT IF} as early in the command file as
-possible. Cases that are deleted early can be processed more
-efficiently in time and space.
-
-When @cmd{SELECT IF} is specified following @cmd{TEMPORARY}
-(@pxref{TEMPORARY}), the @cmd{LAG} function may not be used
-(@pxref{LAG}).
-
-@node SPLIT FILE, TEMPORARY, SELECT IF, Data Selection
-@section SPLIT FILE
-@vindex SPLIT FILE
-
-@display
-Two possible syntaxes:
- SPLIT FILE BY var_list.
- SPLIT FILE OFF.
-@end display
-
-@cmd{SPLIT FILE} allows multiple sets of data present in one data
-file to be analyzed separately using single statistical procedure
-commands.
-
-Specify a list of variable names to analyze multiple sets of
-data separately. Groups of cases having the same values for these
-variables are analyzed by statistical procedure commands as one group.
-An independent analysis is carried out for each group of cases, and the
-variable values for the group are printed along with the analysis.
-
-Specify OFF to disable @cmd{SPLIT FILE} and resume analysis of the
-entire active file as a single group of data.
-
-When @cmd{SPLIT FILE} is specified after @cmd{TEMPORARY}, it affects only
-the next procedure (@pxref{TEMPORARY}).
-
-@node TEMPORARY, WEIGHT, SPLIT FILE, Data Selection
-@section TEMPORARY
-@vindex TEMPORARY
-
-@display
-TEMPORARY.
-@end display
-
-@cmd{TEMPORARY} is used to make the effects of transformations
-following its execution temporary. These transformations will
-affect only the execution of the next procedure or procedure-like
-command. Their effects will not be saved to the active file.
-
-The only specification on @cmd{TEMPORARY} is the command name.
-
-@cmd{TEMPORARY} may not appear within a @cmd{DO IF} or @cmd{LOOP}
-construct. It may appear only once between procedures and
-procedure-like commands.
-
-Scratch variables cannot be used following @cmd{TEMPORARY}.
-
-An example may help to clarify:
-
-@example
-DATA LIST /X 1-2.
-BEGIN DATA.
- 2
- 4
-10
-15
-20
-24
-END DATA.
-COMPUTE X=X/2.
-TEMPORARY.
-COMPUTE X=X+3.
-DESCRIPTIVES X.
-DESCRIPTIVES X.
-@end example
-
-The data read by the first @cmd{DESCRIPTIVES} are 4, 5, 8,
-10.5, 13, 15. The data read by the first @cmd{DESCRIPTIVES} are 1, 2,
-5, 7.5, 10, 12.
-
-@node WEIGHT, , TEMPORARY, Data Selection
-@section WEIGHT
-@vindex WEIGHT
-
-@display
-WEIGHT BY var_name.
-WEIGHT OFF.
-@end display
-
-@cmd{WEIGHT} assigns cases varying weights,
-changing the frequency distribution of the active file. Execution of
-@cmd{WEIGHT} is delayed until data have been read.
-
-If a variable name is specified, @cmd{WEIGHT} causes the values of that
-variable to be used as weighting factors for subsequent statistical
-procedures. Use of keyword BY is optional but recommended. Weighting
-variables must be numeric. Scratch variables may not be used for
-weighting (@pxref{Scratch Variables}).
-
-When OFF is specified, subsequent statistical procedures will weight all
-cases equally.
-
-A positive integer weighting factor @var{w} on a case will yield the
-same statistical output as would replicating the case @var{w} times.
-A weighting factor of 0 is treated for statistical purposes as if the
-case did not exist in the input. Weighting values need not be
-integers, but negative and system-missing values for the weighting
-variable are interpreted as weighting factors of 0. User-missing
-values are not treated specially.
-
-When @cmd{WEIGHT} is specified after @cmd{TEMPORARY}, it affects only
-the next procedure (@pxref{TEMPORARY}).
-
-@cmd{WEIGHT} does not cause cases in the active file to be replicated in
-memory.
-
-@node Conditionals and Looping, Statistics, Data Selection, Top
-@chapter Conditional and Looping Constructs
-@cindex conditionals
-@cindex loops
-@cindex flow of control
-@cindex control flow
-
-This chapter documents PSPP commands used for conditional execution,
-looping, and flow of control.
-
-@menu
-* BREAK:: Exit a loop.
-* DO IF:: Conditionally execute a block of code.
-* DO REPEAT:: Textually repeat a code block.
-* LOOP:: Repeat a block of code.
-@end menu
-
-@node BREAK, DO IF, Conditionals and Looping, Conditionals and Looping
-@section BREAK
-@vindex BREAK
-
-@display
-BREAK.
-@end display
-
-@cmd{BREAK} terminates execution of the innermost currently executing
-@cmd{LOOP} construct.
-
-@cmd{BREAK} is allowed only inside @cmd{LOOP}@dots{}@cmd{END LOOP}.
-@xref{LOOP}, for more details.
-
-@node DO IF, DO REPEAT, BREAK, Conditionals and Looping
-@section DO IF
-@vindex DO IF
-
-@display
-DO IF condition.
- @dots{}
-[ELSE IF condition.
- @dots{}
-]@dots{}
-[ELSE.
- @dots{}]
-END IF.
-@end display
-
-@cmd{DO IF} allows one of several sets of transformations to be
-executed, depending on user-specified conditions.
-
-If the specified boolean expression evaluates as true, then the block
-of code following @cmd{DO IF} is executed. If it evaluates as
-missing, then
-none of the code blocks is executed. If it is false, then
-the boolean expression on the first @cmd{ELSE IF}, if present, is tested in
-turn, with the same rules applied. If all expressions evaluate to
-false, then the @cmd{ELSE} code block is executed, if it is present.
-
-When @cmd{DO IF} or @cmd{ELSE IF} is specified following @cmd{TEMPORARY}
-(@pxref{TEMPORARY}), the @cmd{LAG} function may not be used
-(@pxref{LAG}).
-
-@node DO REPEAT, LOOP, DO IF, Conditionals and Looping
-@section DO REPEAT
-@vindex DO REPEAT
-
-@display
-DO REPEAT repvar_name=expansion@dots{}.
- @dots{}
-END REPEAT [PRINT].
-
-expansion takes one of the following forms:
- var_list
- num_or_range@dots{}
- 'string'@dots{}
-
-num_or_range takes one of the following forms:
- number
- num1 TO num2
-@end display
-
-@cmd{DO REPEAT} repeats a block of code, textually substituting
-different variables, numbers, or strings into the block with each
-repetition.
-
-Specify a repeat variable name followed by an equals sign (@samp{=}) and
-the list of replacements. Replacements can be a list of variables
-(which may be existing variables or new variables or a combination
-thereof), of numbers, or of strings. When new variable names are
-specified, @cmd{DO REPEAT} creates them as numeric variables. When numbers
-are specified, runs of integers may be indicated with TO notation, for
-instance @samp{1 TO 5} and @samp{1 2 3 4 5} would be equivalent. There
-is no equivalent notation for string values.
-
-Multiple repeat variables can be specified. When this is done, each
-variable must have the same number of replacements.
-
-The code within @cmd{DO REPEAT} is repeated as many times as there are
-replacements for each variable. The first time, the first value for
-each repeat variable is substituted; the second time, the second value
-for each repeat variable is substituted; and so on.
-
-Repeat variable substitutions work like macros. They take place
-anywhere in a line that the repeat variable name occurs as a token,
-including command and subcommand names. For this reason it is not a
-good idea to select words commonly used in command and subcommand names
-as repeat variable identifiers.
-
-If PRINT is specified on @cmd{END REPEAT}, the commands after substitutions
-are made are printed to the listing file, prefixed by a plus sign
-(@samp{+}).
-
-@node LOOP, , DO REPEAT, Conditionals and Looping
-@section LOOP
-@vindex LOOP
-
-@display
-LOOP [index_var=start TO end [BY incr]] [IF condition].
- @dots{}
-END LOOP [IF condition].
-@end display
-
-@cmd{LOOP} iterates a group of commands. A number of
-termination options are offered.
-
-Specify index_var to make that variable count from one value to
-another by a particular increment. index_var must be a pre-existing
-numeric variable. start, end, and incr are numeric expressions
-(@pxref{Expressions}.)
-
-During the first iteration, index_var is set to the value of start.
-During each successive iteration, index_var is increased by the value of
-incr. If end > start, then the loop terminates when index_var > end;
-otherwise it terminates when index_var < end. If incr is not specified
-then it defaults to +1 or -1 as appropriate.
-
-If end > start and incr < 0, or if end < start and incr > 0, then the
-loop is never executed. index_var is nevertheless set to the value of
-start.
-
-Modifying index_var within the loop is allowed, but it has no effect on
-the value of index_var in the next iteration.
-
-Specify a boolean expression for the condition on @cmd{LOOP} to
-cause the loop to be executed only if the condition is true. If the
-condition is false or missing before the loop contents are executed the
-first time, the loop contents are not executed at all.
-
-If index and condition clauses are both present on @cmd{LOOP}, the index
-clause is always evaluated first.
-
-Specify a boolean expression for the condition on @cmd{END LOOP} to cause
-the loop to terminate if the condition is not true after the enclosed
-code block is executed. The condition is evaluated at the end of the
-loop, not at the beginning.
-
-If the index clause and both condition clauses are not present, then the
-loop is executed MXLOOPS (@pxref{SET}) times.
-
-@cmd{BREAK} also terminates @cmd{LOOP} execution (@pxref{BREAK}).
-
-When @cmd{LOOP} or @cmd{END LOOP} is specified following @cmd{TEMPORARY}
-(@pxref{TEMPORARY}), the @cmd{LAG} function may not be used
-(@pxref{LAG}).
-
-@node Statistics, Utilities, Conditionals and Looping, Top
-@chapter Statistics
-
-This chapter documents the statistical procedures that PSPP supports so
-far.
-
-@menu
-* DESCRIPTIVES:: Descriptive statistics.
-* FREQUENCIES:: Frequency tables.
-* CROSSTABS:: Crosstabulation tables.
-* T-TEST:: Test hypotheses about means.
-* ONEWAY:: One analysis of variance.
-@end menu
-
-@node DESCRIPTIVES, FREQUENCIES, Statistics, Statistics
-@section DESCRIPTIVES
-
-@vindex DESCRIPTIVES
-@display
-DESCRIPTIVES
- /VARIABLES=var_list
- /MISSING=@{VARIABLE,LISTWISE@} @{INCLUDE,NOINCLUDE@}
- /FORMAT=@{LABELS,NOLABELS@} @{NOINDEX,INDEX@} @{LINE,SERIAL@}
- /SAVE
- /STATISTICS=@{ALL,MEAN,SEMEAN,STDDEV,VARIANCE,KURTOSIS,
- SKEWNESS,RANGE,MINIMUM,MAXIMUM,SUM,DEFAULT,
- SESKEWNESS,SEKURTOSIS@}
- /SORT=@{NONE,MEAN,SEMEAN,STDDEV,VARIANCE,KURTOSIS,SKEWNESS,
- RANGE,MINIMUM,MAXIMUM,SUM,SESKEWNESS,SEKURTOSIS,NAME@}
- @{A,D@}
-@end display
-
-The @cmd{DESCRIPTIVES} procedure reads the active file and outputs
-descriptive
-statistics requested by the user. In addition, it can optionally
-compute Z-scores.
-
-The VARIABLES subcommand, which is required, specifies the list of
-variables to be analyzed. Keyword VARIABLES is optional.
-
-All other subcommands are optional:
-
-The MISSING subcommand determines the handling of missing variables. If
-INCLUDE is set, then user-missing values are included in the
-calculations. If NOINCLUDE is set, which is the default, user-missing
-values are excluded. If VARIABLE is set, then missing values are
-excluded on a variable by variable basis; if LISTWISE is set, then
-the entire case is excluded whenever any value in that case has a
-system-missing or, if INCLUDE is set, user-missing value.
-
-The FORMAT subcommand affects the output format. Currently the
-LABELS/NOLABELS and NOINDEX/INDEX settings are not used. When SERIAL is
-set, both valid and missing number of cases are listed in the output;
-when NOSERIAL is set, only valid cases are listed.
-
-The SAVE subcommand causes @cmd{DESCRIPTIVES} to calculate Z scores for all
-the specified variables. The Z scores are saved to new variables.
-Variable names are generated by trying first the original variable name
-with Z prepended and truncated to a maximum of 8 characters, then the
-names ZSC000 through ZSC999, STDZ00 through STDZ09, ZZZZ00 through
-ZZZZ09, ZQZQ00 through ZQZQ09, in that sequence. In addition, Z score
-variable names can be specified explicitly on VARIABLES in the variable
-list by enclosing them in parentheses after each variable.
-
-The STATISTICS subcommand specifies the statistics to be displayed:
-
-@table @code
-@item ALL
-All of the statistics below.
-@item MEAN
-Arithmetic mean.
-@item SEMEAN
-Standard error of the mean.
-@item STDDEV
-Standard deviation.
-@item VARIANCE
-Variance.
-@item KURTOSIS
-Kurtosis and standard error of the kurtosis.
-@item SKEWNESS
-Skewness and standard error of the skewness.
-@item RANGE
-Range.
-@item MINIMUM
-Minimum value.
-@item MAXIMUM
-Maximum value.
-@item SUM
-Sum.
-@item DEFAULT
-Mean, standard deviation of the mean, minimum, maximum.
-@item SEKURTOSIS
-Standard error of the kurtosis.
-@item SESKEWNESS
-Standard error of the skewness.
-@end table
-
-The SORT subcommand specifies how the statistics should be sorted. Most
-of the possible values should be self-explanatory. NAME causes the
-statistics to be sorted by name. By default, the statistics are listed
-in the order that they are specified on the VARIABLES subcommand. The A
-and D settings request an ascending or descending sort order,
-respectively.
-
-@node FREQUENCIES, CROSSTABS, DESCRIPTIVES, Statistics
-@section FREQUENCIES
-
-@vindex FREQUENCIES
-@display
-FREQUENCIES
- /VARIABLES=var_list
- /FORMAT=@{TABLE,NOTABLE,LIMIT(limit)@}
- @{STANDARD,CONDENSE,ONEPAGE[(onepage_limit)]@}
- @{LABELS,NOLABELS@}
- @{AVALUE,DVALUE,AFREQ,DFREQ@}
- @{SINGLE,DOUBLE@}
- @{OLDPAGE,NEWPAGE@}
- /MISSING=@{EXCLUDE,INCLUDE@}
- /STATISTICS=@{DEFAULT,MEAN,SEMEAN,MEDIAN,MODE,STDDEV,VARIANCE,
- KURTOSIS,SKEWNESS,RANGE,MINIMUM,MAXIMUM,SUM,
- SESKEWNESS,SEKURTOSIS,ALL,NONE@}
- /NTILES=ntiles
- /PERCENTILES=percent@dots{}
-
-(These options are not currently implemented.)
- /BARCHART=@dots{}
- /HISTOGRAM=@dots{}
- /HBAR=@dots{}
- /GROUPED=@dots{}
-
-(Integer mode.)
- /VARIABLES=var_list (low,high)@dots{}
-@end display
-
-The @cmd{FREQUENCIES} procedure outputs frequency tables for specified
-variables.
-@cmd{FREQUENCIES} can also calculate and display descriptive statistics
-(including median and mode) and percentiles.
-
-In the future, @cmd{FREQUENCIES} will also support graphical output in the
-form of bar charts and histograms. In addition, it will be able to
-support percentiles for grouped data.
-
-The VARIABLES subcommand is the only required subcommand. Specify the
-variables to be analyzed. In most cases, this is all that is required.
-This is known as @dfn{general mode}.
-
-Occasionally, one may want to invoke a special mode called @dfn{integer
-mode}. Normally, in general mode, PSPP will automatically determine
-what values occur in the data. In integer mode, the user specifies the
-range of values that the data assumes. To invoke this mode, specify a
-range of data values in parentheses, separated by a comma. Data values
-inside the range are truncated to the nearest integer, then assigned to
-that value. If values occur outside this range, they are discarded.
-
-The FORMAT subcommand controls the output format. It has several
-possible settings:
-
-@itemize @bullet
-@item
-TABLE, the default, causes a frequency table to be output for every
-variable specified. NOTABLE prevents them from being output. LIMIT
-with a numeric argument causes them to be output except when there are
-more than the specified number of values in the table.
-
-@item
-STANDARD frequency tables contain more complete information, but also to
-take up more space on the printed page. CONDENSE frequency tables are
-less informative but take up less space. ONEPAGE with a numeric
-argument will output standard frequency tables if there are the
-specified number of values or less, condensed tables otherwise. ONEPAGE
-without an argument defaults to a threshold of 50 values.
-
-@item
-LABELS causes value labels to be displayed in STANDARD frequency
-tables. NOLABLES prevents this.
-
-@item
-Normally frequency tables are sorted in ascending order by value. This
-is AVALUE. DVALUE tables are sorted in descending order by value.
-AFREQ and DFREQ tables are sorted in ascending and descending order,
-respectively, by frequency count.
-
-@item
-SINGLE spaced frequency tables are closely spaced. DOUBLE spaced
-frequency tables have wider spacing.
-
-@item
-OLDPAGE and NEWPAGE are not currently used.
-@end itemize
-
-The MISSING subcommand controls the handling of user-missing values.
-When EXCLUDE, the default, is set, user-missing values are not included
-in frequency tables or statistics. When INCLUDE is set, user-missing
-are included. System-missing values are never included in statistics,
-but are listed in frequency tables.
-
-The available STATISTICS are the same as available in @cmd{DESCRIPTIVES}
-(@pxref{DESCRIPTIVES}), with the addition of MEDIAN, the data's median
-value, and MODE, the mode. (If there are multiple modes, the smallest
-value is reported.) By default, the mean, standard deviation of the
-mean, minimum, and maximum are reported for each variable.
-
-PERCENTILES causes the specified percentiles to be reported.
-The percentiles should be presented at a list of numbers between 0
-and 100 inclusive.
-The NTILES subcommand causes the percentiles to be reported at the
-boundaries of the data set divided into the specified number of ranges.
-For instance, @code{/NTILES=4} would cause quartiles to be reported.
-
-
-@node CROSSTABS, T-TEST, FREQUENCIES, Statistics
-@section CROSSTABS
-
-@vindex CROSSTABS
-@display
-CROSSTABS
- /TABLES=var_list BY var_list [BY var_list]@dots{}
- /MISSING=@{TABLE,INCLUDE,REPORT@}
- /WRITE=@{NONE,CELLS,ALL@}
- /FORMAT=@{TABLES,NOTABLES@}
- @{LABELS,NOLABELS,NOVALLABS@}
- @{PIVOT,NOPIVOT@}
- @{AVALUE,DVALUE@}
- @{NOINDEX,INDEX@}
- @{BOX,NOBOX@}
- /CELLS=@{COUNT,ROW,COLUMN,TOTAL,EXPECTED,RESIDUAL,SRESIDUAL,
- ASRESIDUAL,ALL,NONE@}
- /STATISTICS=@{CHISQ,PHI,CC,LAMBDA,UC,BTAU,CTAU,RISK,GAMMA,D,
- KAPPA,ETA,CORR,ALL,NONE@}
-
-(Integer mode.)
- /VARIABLES=var_list (low,high)@dots{}
-@end display
-
-The @cmd{CROSSTABS} procedure displays crosstabulation
-tables requested by the user. It can calculate several statistics for
-each cell in the crosstabulation tables. In addition, a number of
-statistics can be calculated for each table itself.
-
-The TABLES subcommand is used to specify the tables to be reported. Any
-number of dimensions is permitted, and any number of variables per
-dimension is allowed. The TABLES subcommand may be repeated as many
-times as needed. This is the only required subcommand in @dfn{general
-mode}.
-
-Occasionally, one may want to invoke a special mode called @dfn{integer
-mode}. Normally, in general mode, PSPP automatically determines
-what values occur in the data. In integer mode, the user specifies the
-range of values that the data assumes. To invoke this mode, specify the
-VARIABLES subcommand, giving a range of data values in parentheses for
-each variable to be used on the TABLES subcommand. Data values inside
-the range are truncated to the nearest integer, then assigned to that
-value. If values occur outside this range, they are discarded. When it
-is present, the VARIABLES subcommand must precede the TABLES
-subcommand.
-
-In general mode, numeric and string variables may be specified on
-TABLES. Although long string variables are allowed, only their
-initial short-string parts are used. In integer mode, only numeric
-variables are allowed.
-
-The MISSING subcommand determines the handling of user-missing values.
-When set to TABLE, the default, missing values are dropped on a table by
-table basis. When set to INCLUDE, user-missing values are included in
-tables and statistics. When set to REPORT, which is allowed only in
-integer mode, user-missing values are included in tables but marked with
-an @samp{M} (for ``missing'') and excluded from statistical
-calculations.
-
-Currently the WRITE subcommand is ignored.
-
-The FORMAT subcommand controls the characteristics of the
-crosstabulation tables to be displayed. It has a number of possible
-settings:
-
-@itemize @bullet
-@item
-TABLES, the default, causes crosstabulation tables to be output.
-NOTABLES suppresses them.
-
-@item
-LABELS, the default, allows variable labels and value labels to appear
-in the output. NOLABELS suppresses them. NOVALLABS displays variable
-labels but suppresses value labels.
-
-@item
-PIVOT, the default, causes each TABLES subcommand to be displayed in a
-pivot table format. NOPIVOT causes the old-style crosstabulation format
-to be used.
-
-@item
-AVALUE, the default, causes values to be sorted in ascending order.
-DVALUE asserts a descending sort order.
-
-@item
-INDEX/NOINDEX is currently ignored.
-
-@item
-BOX/NOBOX is currently ignored.
-@end itemize
-
-The CELLS subcommand controls the contents of each cell in the displayed
-crosstabulation table. The possible settings are:
-
-@table @asis
-@item COUNT
-Frequency count.
-@item ROW
-Row percent.
-@item COLUMN
-Column percent.
-@item TOTAL
-Table percent.
-@item EXPECTED
-Expected value.
-@item RESIDUAL
-Residual.
-@item SRESIDUAL
-Standardized residual.
-@item ASRESIDUAL
-Adjusted standardized residual.
-@item ALL
-All of the above.
-@item NONE
-Suppress cells entirely.
-@end table
-
-@samp{/CELLS} without any settings specified requests COUNT, ROW,
-COLUMN, and TOTAL. If CELLS is not specified at all then only COUNT
-will be selected.
-
-The STATISTICS subcommand selects statistics for computation:
-
-@table @asis
-@item CHISQ
-Pearson chi-square, likelihood ratio, Fisher's exact test, continuity
-correction, linear-by-linear association.
-@item PHI
-Phi.
-@item CC
-Contingency coefficient.
-@item LAMBDA
-Lambda.
-@item UC
-Uncertainty coefficient.
-@item BTAU
-Tau-b.
-@item CTAU
-Tau-c.
-@item RISK
-Risk estimate.
-@item GAMMA
-Gamma.
-@item D
-Somers' D.
-@item KAPPA
-Cohen's Kappa.
-@item ETA
-Eta.
-@item CORR
-Spearman correlation, Pearson's r.
-@item ALL
-All of the above.
-@item NONE
-No statistics.
-@end table
-
-Selected statistics are only calculated when appropriate for the
-statistic. Certain statistics require tables of a particular size, and
-some statistics are calculated only in integer mode.
-
-@samp{/STATISTICS} without any settings selects CHISQ. If the
-STATISTICS subcommand is not given, no statistics are calculated.
-
-@strong{Please note:} Currently the implementation of CROSSTABS has the
-followings bugs:
-
-@itemize @bullet
-@item
-Pearson's R (but not Spearman) is off a little.
-@item
-T values for Spearman's R and Pearson's R are wrong.
-@item
-Significance of symmetric and directional measures is not calculated.
-@item
-Asymmetric ASEs and T values for lambda are wrong.
-@item
-ASE of Goodman and Kruskal's tau is not calculated.
-@item
-ASE of symmetric somers' d is wrong.
-@item
-Approximate T of uncertainty coefficient is wrong.
-@end itemize
-
-Fixes for any of these deficiencies would be welcomed.
-
-@node T-TEST, ONEWAY, CROSSTABS, Statistics
-@comment node-name, next, previous, up
-@section T-TEST
-
-@vindex T-TEST
-@display
-T-TEST
- /MISSING=@{ANALYSIS,LISTWISE@} @{EXCLUDE,INCLUDE@}
- /CRITERIA=CIN(confidence)
-
-
-(One Sample mode.)
- TESTVAL=test_value
- /VARIABLES=var_list
-
-
-(Independent Samples mode.)
- GROUPS=var(value1 [, value2])
- /VARIABLES=var_list
-
-
-(Paired Samples mode.)
- PAIRS=var_list [WITH var_list [(PAIRED)] ]
-
-@end display
-
-
-The @cmd{T-TEST} procedure outputs tables used in testing hypotheses about
-means.
-It operates in one of three modes:
-@itemize
-@item One Sample mode.
-@item Independent Groups mode.
-@item Paired mode.
-@end itemize
-
-@noindent
-Each of these modes are described in more detail below.
-There are two optional subcommands which are common to all modes.
-
-The @cmd{/CRITERIA} subcommand tells PSPP the confidence interval used
-in the tests. The default value is 0.95.
-
-
-The @cmd{MISSING} subcommand determines the handling of missing
-variables.
-If INCLUDE is set, then user-missing values are included in the
-calculations, but system-missing values are not.
-If EXCLUDE is set, which is the default, user-missing
-values are excluded as well as system-missing values.
-This is the default.
-
-If LISTWISE is set, then the entire case is excluded from analysis
-whenever any variable specified in the @cmd{/VARIABLES}, @cmd{/PAIRS} or
-@cmd{/GROUPS} subcommands contains a missing value.
-If ANALYSIS is set, then missing values are excluded only in the analysis for
-which they would be needed. This is the default.
-
-
-@menu
-* One Sample Mode:: Testing against a hypothesised mean
-* Independent Samples Mode:: Testing two independent groups for equal mean
-* Paired Samples Mode:: Testing two interdependent groups for equal mean
-@end menu
-
-@node One Sample Mode, Independent Samples Mode, T-TEST, T-TEST
-@subsection One Sample Mode
-
-The @cmd{TESTVAL} subcommand invokes the One Sample mode.
-This mode is used to test a population mean against a hypothesised
-mean.
-The value given to the @cmd{TESTVAL} subcommand is the value against
-which you wish to test.
-In this mode, you must also use the @cmd{/VARIABLES} subcommand to
-tell PSPP which variables you wish to test.
-
-@node Independent Samples Mode, Paired Samples Mode, One Sample Mode, T-TEST
-@comment node-name, next, previous, up
-@subsection Independent Samples Mode
-
-The @cmd{GROUPS} subcommand invokes Independent Samples mode or
-`Groups' mode.
-This mode is used to test whether two groups of values have the
-same population mean.
-In this mode, you must also use the @cmd{/VARIABLES} subcommand to
-tell PSPP the dependent variables you wish to test.
-
-The variable given in the @cmd{GROUPS} subcommand is the independent
-variable which determines to which group the samples belong.
-The values in parentheses are the specific values of the independent
-variable for each group.
-If the parentheses are omitted and no values are given, the default values
-of 1.0 and 2.0 are assumed.
-
-If the independent variable is numeric,
-it is acceptable to specify only one value inside the parentheses.
-If you do this, cases where the independent variable is
-less than or equal to this value belong to the first group, and cases
-greater than this value belong to the second group.
-When using this form of the @cmd{GROUPS} subcommand, missing values in
-the independent variable are excluded on a listwise basis, regardless
-of whether @cmd{/MISSING=LISTWISE} was specified.
-
-
-@node Paired Samples Mode, , Independent Samples Mode, T-TEST
-@comment node-name, next, previous, up
-@subsection Paired Samples Mode
-
-The @cmd{PAIRS} subcommand introduces Paired Samples mode.
-Use this mode when repeated measures have been taken from the same
-samples.
-If the the @code{WITH} keyword is omitted, then tables for all
-combinations of variables given in the @cmd{PAIRS} subcommand are
-generated.
-If the @code{WITH} keyword is given, and the @code{(PAIRED)} keyword
-is also given, then the number of variables preceding @code{WITH}
-must be the same as the number following it.
-In this case, tables for each respective pair of variables are
-generated.
-In the event that the @code{WITH} keyword is given, but the
-@code{(PAIRED)} keyword is omitted, then tables for each combination
-of variable preceding @code{WITH} against variable following
-@code{WITH} are generated.
-
-
-@node ONEWAY, , T-TEST, Statistics
-@comment node-name, next, previous, up
-@section Oneway
-
-@vindex ONEWAY
-@cindex analysis of variance
-@cindex ANOVA
-
-@display
-ONEWAY
- [/VARIABLES = ] var_list BY var
- /MISSING=@{ANALYSIS,LISTWISE@} @{EXCLUDE,INCLUDE@}
- /CONTRASTS= value1 [, value2] ... [,valueN]
- /STATISTICS=@{DESCRIPTIVES,HOMOGENEITY@}
-
-@end display
-
-The @cmd{ONEWAY} procedure performs a one-way analysis of variance of
-variables factored by a single independent variable.
-It is used to compare the means of a population
-divided into more than two groups.
-
-The variables to be analysed should be given in the @code{VARIABLES}
-subcommand.
-The list of variables must be followed by the @code{BY} keyword and
-the name of the independent (or factor) variable.
-
-You can use the @code{STATISTICS} subcommand to tell PSPP to display
-ancilliary information. The options accepted are:
-@itemize
-@item DESCRIPTIVES
-Displays descriptive statistics about the groups factored by the independent
-variable.
-@item HOMOGENEITY
-Displays the Levene test of Homogeneity of Variance for the
-variables and their groups.
-@end itemize
-
-The @code{CONTRASTS} subcommand is used when you anticipate certain
-differences between the groups.
-The subcommand must be followed by a list of numerals which are the
-coefficients of the groups to be tested.
-The number of coefficients must correspond to the number of distinct
-groups (or values of the independent variable).
-If the total sum of the coefficients are not zero, then PSPP will
-display a warning, but will proceed with the analysis.
-The @code{CONTRASTS} subcommand may be given up to 10 times in order
-to specify different contrast tests.
-
-
-
-@node Utilities, Not Implemented, Statistics, Top
-@chapter Utilities
-
-Commands that don't fit any other category are placed here.
-
-Most of these commands are not affected by commands like @cmd{IF} and
-@cmd{LOOP}:
-they take effect only once, unconditionally, at the time that they are
-encountered in the input.
-
-@menu
-* COMMENT:: Document your syntax file.
-* DOCUMENT:: Document the active file.
-* DISPLAY DOCUMENTS:: Display active file documents.
-* DISPLAY FILE LABEL:: Display the active file label.
-* DROP DOCUMENTS:: Remove documents from the active file.
-* ERASE:: Erase a file.
-* EXECUTE:: Execute pending transformations.
-* FILE LABEL:: Set the active file's label.
-* FINISH:: Terminate the PSPP session.
-* HOST:: Temporarily return to the operating system.
-* INCLUDE:: Include a file within the current one.
-* QUIT:: Terminate the PSPP session.
-* SET:: Adjust PSPP runtime parameters.
-* SHOW:: Display runtime parameters.
-* SUBTITLE:: Provide a document subtitle.
-* TITLE:: Provide a document title.
-@end menu
-
-@node COMMENT, DOCUMENT, Utilities, Utilities
-@section COMMENT
-@vindex COMMENT
-@vindex *
-
-@display
-Two possibles syntaxes:
- COMMENT comment text @dots{} .
- *comment text @dots{} .
-@end display
-
-@cmd{COMMENT} is ignored. It is used to provide information to
-the author and other readers of the PSPP syntax file.
-
-@cmd{COMMENT} can extend over any number of lines. Don't forget to
-terminate it with a dot or a blank line.
-
-@node DOCUMENT, DISPLAY DOCUMENTS, COMMENT, Utilities
-@section DOCUMENT
-@vindex DOCUMENT
-
-@display
-DOCUMENT documentary_text.
-@end display
-
-@cmd{DOCUMENT} adds one or more lines of descriptive commentary to the
-active file. Documents added in this way are saved to system files.
-They can be viewed using @cmd{SYSFILE INFO} or @cmd{DISPLAY
-DOCUMENTS}. They can be removed from the active file with @cmd{DROP
-DOCUMENTS}.
-
-Specify the documentary text following the DOCUMENT keyword. You can
-extend the documentary text over as many lines as necessary. Lines are
-truncated at 80 characters width. Don't forget to terminate
-the command with a dot or a blank line.
-
-@node DISPLAY DOCUMENTS, DISPLAY FILE LABEL, DOCUMENT, Utilities
-@section DISPLAY DOCUMENTS
-@vindex DISPLAY DOCUMENTS
-
-@display
-DISPLAY DOCUMENTS.
-@end display
-
-@cmd{DISPLAY DOCUMENTS} displays the documents in the active file. Each
-document is preceded by a line giving the time and date that it was
-added. @xref{DOCUMENT}.
-
-@node DISPLAY FILE LABEL, DROP DOCUMENTS, DISPLAY DOCUMENTS, Utilities
-@section DISPLAY FILE LABEL
-@vindex DISPLAY FILE LABEL
-
-@display
-DISPLAY FILE LABEL.
-@end display
-
-@cmd{DISPLAY FILE LABEL} displays the file label contained in the
-active file,
-if any. @xref{FILE LABEL}.
-
-@node DROP DOCUMENTS, ERASE, DISPLAY FILE LABEL, Utilities
-@section DROP DOCUMENTS
-@vindex DROP DOCUMENTS
-
-@display
-DROP DOCUMENTS.
-@end display
-
-@cmd{DROP DOCUMENTS} removes all documents from the active file.
-New documents can be added with @cmd{DOCUMENT} (@pxref{DOCUMENT}).
-
-@cmd{DROP DOCUMENTS} changes only the active file. It does not modify any
-system files stored on disk.
-
-
-@node ERASE, EXECUTE, DROP DOCUMENTS, Utilities
-@comment node-name, next, previous, up
-@section ERASE
-@vindex ERASE
-
-@display
-ERASE FILE file_name.
-@end display
-
-@cmd{ERASE FILE} deletes a file from the local filesystem.
-file_name must be quoted.
-This command cannot be used if the SAFER setting is active.
-
-
-@node EXECUTE, FILE LABEL, ERASE, Utilities
-@section EXECUTE
-@vindex EXECUTE
-
-@display
-EXECUTE.
-@end display
-
-@cmd{EXECUTE} causes the active file to be read and all pending
-transformations to be executed.
-
-@node FILE LABEL, FINISH, EXECUTE, Utilities
-@section FILE LABEL
-@vindex FILE LABEL
-
-@display
-FILE LABEL file_label.
-@end display
-
-@cmd{FILE LABEL} provides a title for the active file. This
-title will be saved into system files and portable files that are
-created during this PSPP run.
-
-file_label need not be quoted. If quotes are
-included, they become part of the file label.
-
-@node FINISH, HOST, FILE LABEL, Utilities
-@section FINISH
-@vindex FINISH
-
-@display
-FINISH.
-@end display
-
-@cmd{FINISH} terminates the current PSPP session and returns
-control to the operating system.
-
-This command is not valid in interactive mode.
-
-@node HOST, INCLUDE, FINISH, Utilities
-@comment node-name, next, previous, up
-@section HOST
-@vindex HOST
-
-@display
-HOST.
-@end display
-
-@cmd{HOST} suspends the current PSPP session and temporarily returns control
-to the operating system.
-This command cannot be used if the SAFER setting is active.
-
-
-@node INCLUDE, QUIT, HOST, Utilities
-@section INCLUDE
-@vindex INCLUDE
-@vindex @@
-
-@display
-Two possible syntaxes:
- INCLUDE 'filename'.
- @@filename.
-@end display
-
-@cmd{INCLUDE} causes the PSPP command processor to read an
-additional command file as if it were included bodily in the current
-command file.
-
-Include files may be nested to any depth, up to the limit of available
-memory.
-
-@node QUIT, SET, INCLUDE, Utilities
-@section QUIT
-@vindex QUIT
-
-@display
-Two possible syntaxes:
- QUIT.
- EXIT.
-@end display
-
-@cmd{QUIT} terminates the current PSPP session and returns control
-to the operating system.
-
-This command is not valid within a command file.
-
-@node SET, SHOW, QUIT, Utilities
-@section SET
-@vindex SET
-
-@display
-SET
-
-(data input)
- /BLANKS=@{SYSMIS,'.',number@}
- /DECIMAL=@{DOT,COMMA@}
- /FORMAT=fmt_spec
-
-(program input)
- /ENDCMD='.'
- /NULLINE=@{ON,OFF@}
-
-(interaction)
- /CPROMPT='cprompt_string'
- /DPROMPT='dprompt_string'
- /ERRORBREAK=@{OFF,ON@}
- /MXERRS=max_errs
- /MXWARNS=max_warnings
- /PROMPT='prompt'
- /VIEWLENGTH=@{MINIMUM,MEDIAN,MAXIMUM,n_lines@}
- /VIEWWIDTH=n_characters
-
-(program execution)
- /MEXPAND=@{ON,OFF@}
- /MITERATE=max_iterations
- /MNEST=max_nest
- /MPRINT=@{ON,OFF@}
- /MXLOOPS=max_loops
- /SEED=@{RANDOM,seed_value@}
- /UNDEFINED=@{WARN,NOWARN@}
-
-(data output)
- /CC@{A,B,C,D,E@}=@{'npre,pre,suf,nsuf','npre.pre.suf.nsuf'@}
- /DECIMAL=@{DOT,COMMA@}
- /FORMAT=fmt_spec
-
-(output routing)
- /ECHO=@{ON,OFF@}
- /ERRORS=@{ON,OFF,TERMINAL,LISTING,BOTH,NONE@}
- /INCLUDE=@{ON,OFF@}
- /MESSAGES=@{ON,OFF,TERMINAL,LISTING,BOTH,NONE@}
- /PRINTBACK=@{ON,OFF@}
- /RESULTS=@{ON,OFF,TERMINAL,LISTING,BOTH,NONE@}
-
-(output activation)
- /LISTING=@{ON,OFF@}
- /PRINTER=@{ON,OFF@}
- /SCREEN=@{ON,OFF@}
-
-(output driver options)
- /HEADERS=@{NO,YES,BLANK@}
- /LENGTH=@{NONE,length_in_lines@}
- /LISTING=filename
- /MORE=@{ON,OFF@}
- /PAGER=@{OFF,"pager_name"@}
- /WIDTH=@{NARROW,WIDTH,n_characters@}
-
-(logging)
- /JOURNAL=@{ON,OFF@} [filename]
- /LOG=@{ON,OFF@} [filename]
-
-(system files)
- /COMPRESSION=@{ON,OFF@}
- /SCOMPRESSION=@{ON,OFF@}
-
-(security)
- /SAFER=ON
-
-(obsolete settings accepted for compatibility, but ignored)
- /AUTOMENU=@{ON,OFF@}
- /BEEP=@{ON,OFF@}
- /BLOCK='c'
- /BOXSTRING=@{'xxx','xxxxxxxxxxx'@}
- /CASE=@{UPPER,UPLOW@}
- /COLOR=@dots{}
- /CPI=cpi_value
- /DISK=@{ON,OFF@}
- /EJECT=@{ON,OFF@}
- /HELPWINDOWS=@{ON,OFF@}
- /HIGHRES=@{ON,OFF@}
- /HISTOGRAM='c'
- /LOWRES=@{AUTO,ON,OFF@}
- /LPI=lpi_value
- /MENUS=@{STANDARD,EXTENDED@}
- /MXMEMORY=max_memory
- /PTRANSLATE=@{ON,OFF@}
- /RCOLORS=@dots{}
- /RUNREVIEW=@{AUTO,MANUAL@}
- /SCRIPTTAB='c'
- /TB1=@{'xxx','xxxxxxxxxxx'@}
- /TBFONTS='string'
- /WORKDEV=drive_letter
- /WORKSPACE=workspace_size
- /XSORT=@{YES,NO@}
-@end display
-
-@cmd{SET} allows the user to adjust several parameters relating to
-PSPP's execution. Since there are many subcommands to this command, its
-subcommands will be examined in groups.
-
-On subcommands that take boolean values, ON and YES are synonym, and
-as are OFF and NO, when used as subcommand values.
-
-The data input subcommands affect the way that data is read from data
-files. The data input subcommands are
-
-@table @asis
-@item BLANKS
-This is the value assigned to an item data item that is empty or
-contains only whitespace. An argument of SYSMIS or '.' will cause the
-system-missing value to be assigned to null items. This is the
-default. Any real value may be assigned.
-
-@item DECIMAL
-The default DOT setting causes the decimal point character to be
-@samp{.}. A setting of COMMA causes the decimal point character to be
-@samp{,}.
-
-@item FORMAT
-Allows the default numeric input/output format to be specified. The
-default is F8.2. @xref{Input/Output Formats}.
-@end table
-
-Program input subcommands affect the way that programs are parsed when
-they are typed interactively or run from a script. They are
-
-@table @asis
-@item ENDCMD
-This is a single character indicating the end of a command. The default
-is @samp{.}. Don't change this.
-
-@item NULLINE
-Whether a blank line is interpreted as ending the current command. The
-default is ON.
-@end table
-
-Interaction subcommands affect the way that PSPP interacts with an
-online user. The interaction subcommands are
-
-@table @asis
-@item CPROMPT
-The command continuation prompt. The default is @samp{ > }.
-
-@item DPROMPT
-Prompt used when expecting data input within @cmd{BEGIN DATA} (@pxref{BEGIN
-DATA}). The default is @samp{data> }.
-
-@item ERRORBREAK
-Whether an error causes PSPP to stop processing the current command
-file after finishing the current command. The default is OFF.
-
-@item MXERRS
-The maximum number of errors before PSPP halts processing of the current
-command file. The default is 50.
-
-@item MXWARNS
-The maximum number of warnings + errors before PSPP halts processing the
-current command file. The default is 100.
-
-@item PROMPT
-The command prompt. The default is @samp{PSPP> }.
-
-@item VIEWLENGTH
-The length of the screen in lines. MINIMUM means 25 lines, MEDIAN and
-MAXIMUM mean 43 lines. Otherwise specify the number of lines. Normally
-PSPP should auto-detect your screen size so this shouldn't have to be
-used.
-
-@item VIEWWIDTH
-The width of the screen in characters. Normally 80 or 132.
-@end table
-
-Program execution subcommands control the way that PSPP commands
-execute. The program execution subcommands are
-
-@table @asis
-@item MEXPAND
-@itemx MITERATE
-@itemx MNEST
-@itemx MPRINT
-Currently not used.
-
-@item MXLOOPS
-The maximum number of iterations for an uncontrolled loop (@pxref{LOOP}).
-
-@item SEED
-The initial pseudo-random number seed. Set to a real number or to
-RANDOM, which will obtain an initial seed from the current time of day.
-
-@item UNDEFINED
-Currently not used.
-@end table
-
-Data output subcommands affect the format of output data. These
-subcommands are
-
-@table @asis
-@item CCA
-@itemx CCB
-@itemx CCC
-@itemx CCD
-@itemx CCE
-Set up custom currency formats. The argument is a string which must
-contain exactly three commas or exactly three periods. If commas, then
-the grouping character for the currency format is @samp{,}, and the
-decimal point character is @samp{.}; if periods, then the situation is
-reversed.
-
-The commas or periods divide the string into four fields, which are, in
-order, the negative prefix, prefix, suffix, and negative suffix. When a
-value is formatted using the custom currency format, the prefix precedes
-the value formatted and the suffix follows it. In addition, if the
-value is negative, the negative prefix precedes the prefix and the
-negative suffix follows the suffix.
-
-@item DECIMAL
-The default DOT setting causes the decimal point character to be
-@samp{.}. A setting of COMMA causes the decimal point character to be
-@samp{,}.
-
-@item FORMAT
-Allows the default numeric input/output format to be specified. The
-default is F8.2. @xref{Input/Output Formats}.
-@end table
-
-Output routing subcommands affect where the output of transformations
-and procedures is sent. These subcommands are
-
-@table @asis
-@item ECHO
-
-If turned on, commands are written to the listing file as they are read
-from command files. The default is OFF.
-
-@itemx ERRORS
-@itemx INCLUDE
-@itemx MESSAGES
-@item PRINTBACK
-@item RESULTS
-Currently not used.
-@end table
-
-Output activation subcommands affect whether output devices of
-particular types are enabled. These subcommands are
-
-@table @asis
-@item LISTING
-Enable or disable listing devices.
-
-@item PRINTER
-Enable or disable printer devices.
-
-@item SCREEN
-Enable or disable screen devices.
-@end table
-
-Output driver option subcommands affect output drivers' settings. These
-subcommands are
-
-@table @asis
-@item HEADERS
-@itemx LENGTH
-@itemx LISTING
-@itemx MORE
-@itemx PAGER
-@itemx WIDTH
-Currently not used.
-@end table
-
-Logging subcommands affect logging of commands executed to external
-files. These subcommands are
-
-@table @asis
-@item JOURNAL
-@item LOG
-Not currently used.
-@end table
-
-System file subcommands affect the default format of system files
-produced by PSPP. These subcommands are
-
-@table @asis
-@item COMPRESSION
-Not currently used.
-
-@item SCOMPRESSION
-Whether system files created by @cmd{SAVE} or @cmd{XSAVE} are
-compressed by default. The default is ON.
-@end table
-
-Security subcommands affect the operations that commands are allowed to
-perform. The security subcommands are
-
-@table @asis
-@item SAFER
-When set, this setting cannot ever be reset, for obvious security
-reasons. Setting this option disables the following operations:
-
-@itemize @bullet
-@item
-The ERASE command.
-@item
-The HOST command.
-@item
-Pipe filenames (filenames beginning or ending with @samp{|}).
-@end itemize
-
-Be aware that this setting does not guarantee safety (commands can still
-overwrite files, for instance) but it is an improvement.
-@end table
-
-@node SHOW, SUBTITLE, SET, Utilities
-@comment node-name, next, previous, up
-@section SHOW
-@vindex SHOW
-
-@display
-SHOW
- /@var{subcommand}
-
-@end display
-
-@cmd{SHOW} can be used to display the current state of PSPP's
-execution parameters. All of the parameters which can be changed
-using @code{SET} @xref{SET}, can be examined using @cmd{SHOW}, by
-using a subcommand with the same name.
-In addition, @code{SHOW} supports the following subcommands:
-
-@table @code
-@item WARRANTY
-Show details of the lack of warranty for PSPP.
-@item COPYING
-Display the terms of PSPP's copyright licence @ref{License}.
-@end table
-
-
-
-@node SUBTITLE, TITLE, SHOW, Utilities
-@section SUBTITLE
-@vindex SUBTITLE
-
-@display
-SUBTITLE 'subtitle_string'.
- or
-SUBTITLE subtitle_string.
-@end display
-
-@cmd{SUBTITLE} provides a subtitle to a particular PSPP
-run. This subtitle appears at the top of each output page below the
-title, if headers are enabled on the output device.
-
-Specify a subtitle as a string in quotes. The alternate syntax that did
-not require quotes is now obsolete. If it is used then the subtitle is
-converted to all uppercase.
-
-@node TITLE, , SUBTITLE, Utilities
-@section TITLE
-@vindex TITLE
-
-@display
-TITLE 'title_string'.
- or
-TITLE title_string.
-@end display
-
-@cmd{TITLE} provides a title to a particular PSPP run.
-This title appears at the top of each output page, if headers are enabled
-on the output device.
-
-Specify a title as a string in quotes. The alternate syntax that did
-not require quotes is now obsolete. If it is used then the title is
-converted to all uppercase.
-
-@node Not Implemented, Data File Format, Utilities, Top
-@chapter Not Implemented
-
-This chapter lists parts of the PSPP language that are not yet
-implemented.
-
-The following transformations and utilities are not yet implemented, but
-they will be supported in a later release.
-
-@itemize @bullet
-@item
-ADD FILES
-@item
-ANOVA
-@item
-DEFINE
-@item
-FILE TYPE
-@item
-GET SAS
-@item
-GET TRANSLATE
-@item
-MCONVERT
-@item
-PLOT
-@item
-PRESERVE
-@item
-PROCEDURE OUTPUT
-@item
-RESTORE
-@item
-SAVE TRANSLATE
-@item
-SHOW
-@item
-UPDATE
-@end itemize
-
-The following transformations and utilities are not implemented. There
-are no plans to support them in future releases. Contributions to
-implement them will still be accepted.
-
-@itemize @bullet
-@item
-EDIT
-@item
-GET DATABASE
-@item
-GET OSIRIS
-@item
-GET SCSS
-@item
-GSET
-@item
-HELP
-@item
-INFO
-@item
-INPUT MATRIX
-@item
-KEYED DATA LIST
-@item
-NUMBERED and UNNUMBERED
-@item
-OPTIONS
-@item
-REVIEW
-@item
-SAVE SCSS
-@item
-SPSS MANAGER
-@item
-STATISTICS
-@end itemize
-
-@node Data File Format, Portable File Format, Not Implemented, Top
-@chapter Data File Format
-
-PSPP necessarily uses the same format for system files as do the
-products with which it is compatible. This chapter is a description of
-that format.
-
-There are three data types used in system files: 32-bit integers, 64-bit
-floating points, and 1-byte characters. In this document these will
-simply be referred to as @code{int32}, @code{flt64}, and @code{char},
-the names that are used in the PSPP source code. Every field of type
-@code{int32} or @code{flt64} is aligned on a 32-bit boundary.
-
-The endianness of data in PSPP system files is not specified. System
-files output on a computer of a particular endianness will have the
-endianness of that computer. However, PSPP can read files of either
-endianness, regardless of its host computer's endianness. PSPP
-translates endianness for both integer and floating point numbers.
-
-Floating point formats are also not specified. PSPP does not
-translate between floating point formats. This is unlikely to be a
-problem as all modern computer architectures use IEEE 754 format for
-floating point representation.
-
-The PSPP system-missing value is represented by the largest possible
-negative number in the floating point format; in C, this is most likely
-@code{-DBL_MAX}. There are two other important values used in missing
-values: @code{HIGHEST} and @code{LOWEST}. These are represented by the
-largest possible positive number (probably @code{DBL_MAX}) and the
-second-largest negative number. The latter must be determined in a
-system-dependent manner; in IEEE 754 format it is represented by value
-@code{0xffeffffffffffffe}.
-
-System files are divided into records. Each record begins with an
-@code{int32} giving a numeric record type. Individual record types are
-described below:
-
-@menu
-* File Header Record::
-* Variable Record::
-* Value Label Record::
-* Value Label Variable Record::
-* Document Record::
-* Machine int32 Info Record::
-* Machine flt64 Info Record::
-* Miscellaneous Informational Records::
-* Dictionary Termination Record::
-* Data Record::
-@end menu
-
-@node File Header Record, Variable Record, Data File Format, Data File Format
-@section File Header Record
-
-The file header is always the first record in the file.
-
-@example
-struct sysfile_header
- @{
- char rec_type[4];
- char prod_name[60];
- int32 layout_code;
- int32 case_size;
- int32 compressed;
- int32 weight_index;
- int32 ncases;
- flt64 bias;
- char creation_date[9];
- char creation_time[8];
- char file_label[64];
- char padding[3];
- @};
-@end example
-
-@table @code
-@item char rec_type[4];
-Record type code. Always set to @samp{$FL2}. This is the only record
-for which the record type is not of type @code{int32}.
-
-@item char prod_name[60];
-Product identification string. This always begins with the characters
-@samp{@@(#) SPSS DATA FILE}. PSPP uses the remaining characters to
-give its version and the operating system name; for example, @samp{GNU
-pspp 0.1.4 - sparc-sun-solaris2.5.2}. The string is truncated if it
-would be longer than 60 characters; otherwise it is padded on the right
-with spaces.
-
-@item int32 layout_code;
-Always set to 2. PSPP reads this value to determine the
-file's endianness.
-
-@item int32 case_size;
-Number of data elements per case. This is the number of variables,
-except that long string variables add extra data elements (one for every
-8 characters after the first 8).
-
-@item int32 compressed;
-Set to 1 if the data in the file is compressed, 0 otherwise.
-
-@item int32 weight_index;
-If one of the variables in the data set is used as a weighting variable,
-set to the index of that variable. Otherwise, set to 0.
-
-@item int32 ncases;
-Set to the number of cases in the file if it is known, or -1 otherwise.
-
-In the general case it is not possible to determine the number of cases
-that will be output to a system file at the time that the header is
-written. The way that this is dealt with is by writing the entire
-system file, including the header, then seeking back to the beginning of
-the file and writing just the @code{ncases} field. For `files' in which
-this is not valid, the seek operation fails. In this case,
-@code{ncases} remains -1.
-
-@item flt64 bias;
-Compression bias. Always set to 100. The significance of this value is
-that only numbers between @code{(1 - bias)} and @code{(251 - bias)} can
-be compressed.
-
-@item char creation_date[9];
-Set to the date of creation of the system file, in @samp{dd mmm yy}
-format, with the month as standard English abbreviations, using an
-initial capital letter and following with lowercase. If the date is not
-available then this field is arbitrarily set to @samp{01 Jan 70}.
-
-@item char creation_time[8];
-Set to the time of creation of the system file, in @samp{hh:mm:ss}
-format and using 24-hour time. If the time is not available then this
-field is arbitrarily set to @samp{00:00:00}.
-
-@item char file_label[64];
-Set the the file label declared by the user, if any. Padded on the
-right with spaces.
-
-@item char padding[3];
-Ignored padding bytes to make the structure a multiple of 32 bits in
-length. Set to zeros.
-@end table
-
-@node Variable Record, Value Label Record, File Header Record, Data File Format
-@section Variable Record
-
-Immediately following the header must come the variable records. There
-must be one variable record for every variable and every 8 characters in
-a long string beyond the first 8; i.e., there must be exactly as many
-variable records as the value specified for @code{case_size} in the file
-header record.
-
-@example
-struct sysfile_variable
- @{
- int32 rec_type;
- int32 type;
- int32 has_var_label;
- int32 n_missing_values;
- int32 print;
- int32 write;
- char name[8];
-
- /* The following two fields are present
- only if has_var_label is 1. */
- int32 label_len;
- char label[/* variable length */];
-
- /* The following field is present only
- if n_missing_values is not 0. */
- flt64 missing_values[/* variable length*/];
- @};
-@end example
-
-@table @code
-@item int32 rec_type;
-Record type code. Always set to 2.
-
-@item int32 type;
-Variable type code. Set to 0 for a numeric variable. For a short
-string variable or the first part of a long string variable, this is set
-to the width of the string. For the second and subsequent parts of a
-long string variable, set to -1, and the remaining fields in the
-structure are ignored.
-
-@item int32 has_var_label;
-If this variable has a variable label, set to 1; otherwise, set to 0.
-
-@item int32 n_missing_values;
-If the variable has no missing values, set to 0. If the variable has
-one, two, or three discrete missing values, set to 1, 2, or 3,
-respectively. If the variable has a range for missing variables, set to
--2; if the variable has a range for missing variables plus a single
-discrete value, set to -3.
-
-@item int32 print;
-Print format for this variable. See below.
-
-@item int32 write;
-Write format for this variable. See below.
-
-@item char name[8];
-Variable name. The variable name must begin with a capital letter or
-the at-sign (@samp{@@}). Subsequent characters may also be octothorpes
-(@samp{#}), dollar signs (@samp{$}), underscores (@samp{_}), or full
-stops (@samp{.}). The variable name is padded on the right with spaces.
-
-@item int32 label_len;
-This field is present only if @code{has_var_label} is set to 1. It is
-set to the length, in characters, of the variable label, which must be a
-number between 0 and 120.
-
-@item char label[/* variable length */];
-This field is present only if @code{has_var_label} is set to 1. It has
-length @code{label_len}, rounded up to the nearest multiple of 32 bits.
-The first @code{label_len} characters are the variable's variable label.
-
-@item flt64 missing_values[/* variable length */];
-This field is present only if @code{n_missing_values} is not 0. It has
-the same number of elements as the absolute value of
-@code{n_missing_values}. For discrete missing values, each element
-represents one missing value. When a range is present, the first
-element denotes the minimum value in the range, and the second element
-denotes the maximum value in the range. When a range plus a value are
-present, the third element denotes the additional discrete missing
-value. HIGHEST and LOWEST are indicated as described in the chapter
-introduction.
-@end table
-
-The @code{print} and @code{write} members of sysfile_variable are output
-formats coded into @code{int32} types. The LSB (least-significant byte)
-of the @code{int32} represents the number of decimal places, and the
-next two bytes in order of increasing significance represent field width
-and format type, respectively. The MSB (most-significant byte) is not
-used and should be set to zero.
-
-Format types are defined as follows:
-@table @asis
-@item 0
-Not used.
-@item 1
-@code{A}
-@item 2
-@code{AHEX}
-@item 3
-@code{COMMA}
-@item 4
-@code{DOLLAR}
-@item 5
-@code{F}
-@item 6
-@code{IB}
-@item 7
-@code{PIBHEX}
-@item 8
-@code{P}
-@item 9
-@code{PIB}
-@item 10
-@code{PK}
-@item 11
-@code{RB}
-@item 12
-@code{RBHEX}
-@item 13
-Not used.
-@item 14
-Not used.
-@item 15
-@code{Z}
-@item 16
-@code{N}
-@item 17
-@code{E}
-@item 18
-Not used.
-@item 19
-Not used.
-@item 20
-@code{DATE}
-@item 21
-@code{TIME}
-@item 22
-@code{DATETIME}
-@item 23
-@code{ADATE}
-@item 24
-@code{JDATE}
-@item 25
-@code{DTIME}
-@item 26
-@code{WKDAY}
-@item 27
-@code{MONTH}
-@item 28
-@code{MOYR}
-@item 29
-@code{QYR}
-@item 30
-@code{WKYR}
-@item 31
-@code{PCT}
-@item 32
-@code{DOT}
-@item 33
-@code{CCA}
-@item 34
-@code{CCB}
-@item 35
-@code{CCC}
-@item 36
-@code{CCD}
-@item 37
-@code{CCE}
-@item 38
-@code{EDATE}
-@item 39
-@code{SDATE}
-@end table
-
-@node Value Label Record, Value Label Variable Record, Variable Record, Data File Format
-@section Value Label Record
-
-Value label records must follow the variable records and must precede
-the header termination record. Other than this, they may appear
-anywhere in the system file. Every value label record must be
-immediately followed by a label variable record, described below.
-
-Value label records begin with @code{rec_type}, an @code{int32} value
-set to the record type of 3. This is followed by @code{count}, an
-@code{int32} value set to the number of value labels present in this
-record.
-
-These two fields are followed by a series of @code{count} tuples. Each
-tuple is divided into two fields, the value and the label. The first of
-these, the value, is composed of a 64-bit value, which is either a
-@code{flt64} value or up to 8 characters (padded on the right to 8
-bytes) denoting a short string value. Whether the value is a
-@code{flt64} or a character string is not defined inside the value label
-record.
-
-The second field in the tuple, the label, has variable length. The
-first @code{char} is a count of the number of characters in the value
-label. The remainder of the field is the label itself. The field is
-padded on the right to a multiple of 64 bits in length.
-
-@node Value Label Variable Record, Document Record, Value Label Record, Data File Format
-@section Value Label Variable Record
-
-Every value label variable record must be immediately preceded by a
-value label record, described above.
-
-@example
-struct sysfile_value_label_variable
- @{
- int32 rec_type;
- int32 count;
- int32 vars[/* variable length */];
- @};
-@end example
-
-@table @code
-@item int32 rec_type;
-Record type. Always set to 4.
-
-@item int32 count;
-Number of variables that the associated value labels from the value
-label record are to be applied.
-
-@item int32 vars[/* variable length];
-A list of variables to which to apply the value labels. There are
-@code{count} elements.
-@end table
-
-@node Document Record, Machine int32 Info Record, Value Label Variable Record, Data File Format
-@section Document Record
-
-There must be no more than one document record per system file.
-Document records must follow the variable records and precede the
-dictionary termination record.
-
-@example
-struct sysfile_document
- @{
- int32 rec_type;
- int32 n_lines;
- char lines[/* variable length */][80];
- @};
-@end example
-
-@table @code
-@item int32 rec_type;
-Record type. Always set to 6.
-
-@item int32 n_lines;
-Number of lines of documents present.
-
-@item char lines[/* variable length */][80];
-Document lines. The number of elements is defined by @code{n_lines}.
-Lines shorter than 80 characters are padded on the right with spaces.
-@end table
-
-@node Machine int32 Info Record, Machine flt64 Info Record, Document Record, Data File Format
-@section Machine @code{int32} Info Record
-
-There must be no more than one machine @code{int32} info record per
-system file. Machine @code{int32} info records must follow the variable
-records and precede the dictionary termination record.
-
-@example
-struct sysfile_machine_int32_info
- @{
- /* Header. */
- int32 rec_type;
- int32 subtype;
- int32 size;
- int32 count;
-
- /* Data. */
- int32 version_major;
- int32 version_minor;
- int32 version_revision;
- int32 machine_code;
- int32 floating_point_rep;
- int32 compression_code;
- int32 endianness;
- int32 character_code;
- @};
-@end example
-
-@table @code
-@item int32 rec_type;
-Record type. Always set to 7.
-
-@item int32 subtype;
-Record subtype. Always set to 3.
-
-@item int32 size;
-Size of each piece of data in the data part, in bytes. Always set to 4.
-
-@item int32 count;
-Number of pieces of data in the data part. Always set to 8.
-
-@item int32 version_major;
-PSPP major version number. In version @var{x}.@var{y}.@var{z}, this
-is @var{x}.
-
-@item int32 version_minor;
-PSPP minor version number. In version @var{x}.@var{y}.@var{z}, this
-is @var{y}.
-
-@item int32 version_revision;
-PSPP version revision number. In version @var{x}.@var{y}.@var{z},
-this is @var{z}.
-
-@item int32 machine_code;
-Machine code. PSPP always set this field to value to -1, but other
-values may appear.
-
-@item int32 floating_point_rep;
-Floating point representation code. For IEEE 754 systems this is 1.
-IBM 370 sets this to 2, and DEC VAX E to 3.
-
-@item int32 compression_code;
-Compression code. Always set to 1.
-
-@item int32 endianness;
-Machine endianness. 1 indicates big-endian, 2 indicates little-endian.
-
-@item int32 character_code;
-Character code. 1 indicates EBCDIC, 2 indicates 7-bit ASCII, 3
-indicates 8-bit ASCII, 4 indicates DEC Kanji.
-@end table
-
-@node Machine flt64 Info Record, Miscellaneous Informational Records, Machine int32 Info Record, Data File Format
-@section Machine @code{flt64} Info Record
-
-There must be no more than one machine @code{flt64} info record per
-system file. Machine @code{flt64} info records must follow the variable
-records and precede the dictionary termination record.
-
-@example
-struct sysfile_machine_flt64_info
- @{
- /* Header. */
- int32 rec_type;
- int32 subtype;
- int32 size;
- int32 count;
-
- /* Data. */
- flt64 sysmis;
- flt64 highest;
- flt64 lowest;
- @};
-@end example
-
-@table @code
-@item int32 rec_type;
-Record type. Always set to 7.
-
-@item int32 subtype;
-Record subtype. Always set to 4.
-
-@item int32 size;
-Size of each piece of data in the data part, in bytes. Always set to 4.
-
-@item int32 count;
-Number of pieces of data in the data part. Always set to 3.
-
-@item flt64 sysmis;
-The system missing value.
-
-@item flt64 highest;
-The value used for HIGHEST in missing values.
-
-@item flt64 lowest;
-The value used for LOWEST in missing values.
-@end table
-
-@node Miscellaneous Informational Records, Dictionary Termination Record, Machine flt64 Info Record, Data File Format
-@section Miscellaneous Informational Records
-
-Miscellaneous informational records must follow the variable records and
-precede the dictionary termination record.
-
-Miscellaneous informational records are ignored by PSPP when reading
-system files. They are not written by PSPP when writing system files.
-
-@example
-struct sysfile_misc_info
- @{
- /* Header. */
- int32 rec_type;
- int32 subtype;
- int32 size;
- int32 count;
-
- /* Data. */
- char data[/* variable length */];
- @};
-@end example
-
-@table @code
-@item int32 rec_type;
-Record type. Always set to 7.
-
-@item int32 subtype;
-Record subtype. May take any value. According to Aapi
-H@"am@"al@"ainen, value 5 indicates a set of grouped variables and 6
-indicates date info (probably related to USE).
-
-@item int32 size;
-Size of each piece of data in the data part. Should have the value 4 or
-8, for @code{int32} and @code{flt64}, respectively.
-
-@item int32 count;
-Number of pieces of data in the data part.
-
-@item char data[/* variable length */];
-Arbitrary data. There must be @code{size} times @code{count} bytes of
-data.
-@end table
-
-@node Dictionary Termination Record, Data Record, Miscellaneous Informational Records, Data File Format
-@section Dictionary Termination Record
-
-The dictionary termination record must follow all other records, except
-for the actual cases, which it must precede. There must be exactly one
-dictionary termination record in every system file.
-
-@example
-struct sysfile_dict_term
- @{
- int32 rec_type;
- int32 filler;
- @};
-@end example
-
-@table @code
-@item int32 rec_type;
-Record type. Always set to 999.
-
-@item int32 filler;
-Ignored padding. Should be set to 0.
-@end table
-
-@node Data Record, , Dictionary Termination Record, Data File Format
-@section Data Record
-
-Data records must follow all other records in the data file. There must
-be at least one data record in every system file.
-
-The format of data records varies depending on whether the data is
-compressed. Regardless, the data is arranged in a series of 8-byte
-elements.
-
-When data is not compressed, Every case is composed of @code{case_size}
-of these 8-byte elements, where @code{case_size} comes from the file
-header record (@pxref{File Header Record}). Each element corresponds to
-the variable declared in the respective variable record (@pxref{Variable
-Record}). Numeric values are given in @code{flt64} format; string
-values are literal characters string, padded on the right when
-necessary.
-
-Compressed data is arranged in the following manner: the first 8-byte
-element in the data section is divided into a series of 1-byte command
-codes. These codes have meanings as described below:
-
-@table @asis
-@item 0
-Ignored. If the program writing the system file accumulates compressed
-data in blocks of fixed length, 0 bytes can be used to pad out extra
-bytes remaining at the end of a fixed-size block.
-
-@item 1 through 251
-These values indicate that the corresponding numeric variable has the
-value @code{(@var{code} - @var{bias})} for the case being read, where
-@var{code} is the value of the compression code and @var{bias} is the
-variable @code{compression_bias} from the file header. For example,
-code 105 with bias 100.0 (the normal value) indicates a numeric variable
-of value 5.
-
-@item 252
-End of file. This code may or may not appear at the end of the data
-stream. PSPP always outputs this code but its use is not required.
-
-@item 253
-This value indicates that the numeric or string value is not
-compressible. The value is stored in the 8-byte element following the
-current block of command bytes. If this value appears twice in a block
-of command bytes, then it indicates the second element following the
-command bytes, and so on.
-
-@item 254
-Used to indicate a string value that is all spaces.
-
-@item 255
-Used to indicate the system-missing value.
-@end table
-
-When the end of the first 8-byte element of command bytes is reached,
-any blocks of non-compressible values are skipped, and the next element
-of command bytes is read and interpreted, until the end of the file is
-reached.
-
-@node Portable File Format, q2c Input Format, Data File Format, Top
-@chapter Portable File Format
-
-These days, most computers use the same internal data formats for
-integer and floating-point data, if one ignores little differences like
-big- versus little-endian byte ordering. However, occasionally it is
-necessary to exchange data between systems with incompatible data
-formats. This is what portable files are designed to do.
-
-@strong{Please note:} Although all of the following information is
-correct, as far as the author has been able to ascertain, it is gleaned
-from examination of ASCII-formatted portable files only, so some of it
-may be incorrect in the general case.
-
-@menu
-* Portable File Characters::
-* Portable File Structure::
-* Portable File Header::
-* Version and Date Info Record::
-* Identification Records::
-* Variable Count Record::
-* Case Weight Variable Record::
-* Variable Records::
-* Value Label Records::
-* Portable File Data::
-@end menu
-
-@node Portable File Characters, Portable File Structure, Portable File Format, Portable File Format
-@section Portable File Characters
-
-Portable files are arranged as a series of lines of exactly 80
-characters each. Each line is terminated by a carriage-return,
-line-feed sequence ``new-lines''). New-lines are only used to avoid
-line length limits imposed by some OSes; they are not meaningful.
-
-The file must be terminated with a @samp{Z} character. In addition, if
-the final line in the file does not have exactly 80 characters, then it
-is padded on the right with @samp{Z} characters. (The file contents may
-be in any character set; the file contains a description of its own
-character set, as explained in the next section. Therefore, the
-@samp{Z} character is not necessarily an ASCII @samp{Z}.)
-
-For the rest of the description of the portable file format, new-lines
-and the trailing @samp{Z}s will be ignored, as if they did not exist,
-because they are not an important part of understanding the file
-contents.
-
-@node Portable File Structure, Portable File Header, Portable File Characters, Portable File Format
-@section Portable File Structure
-
-Every portable file consists of the following records, in sequence:
-
-@itemize @bullet
-
-@item
-File header.
-
-@item
-Version and date info.
-
-@item
-Product identification.
-
-@item
-Subproduct identification (optional).
-
-@item
-Variable count.
-
-@item
-Case weight variable (optional).
-
-@item
-Variables. Each variable record may optionally be followed by a
-missing value record and a variable label record.
-
-@item
-Value labels (optional).
-
-@item
-Data.
-@end itemize
-
-Most records are identified by a single-character tag code. The file
-header and version info record do not have a tag.
-
-Other than these single-character codes, there are three types of fields
-in a portable file: floating-point, integer, and string. Floating-point
-fields have the following format:
-
-@itemize @bullet
-
-@item
-Zero or more leading spaces.
-
-@item
-Optional asterisk (@samp{*}), which indicates a missing value. The
-asterisk must be followed by a single character, generally a period
-(@samp{.}), but it appears that other characters may also be possible.
-This completes the specification of a missing value.
-
-@item
-Optional minus sign (@samp{-}) to indicate a negative number.
-
-@item
-A whole number, consisting of one or more base-30 digits: @samp{0}
-through @samp{9} plus capital letters @samp{A} through @samp{T}.
-
-@item
-Optional fraction, consisting of a radix point (@samp{.}) followed by
-one or more base-30 digits.
-
-@item
-Optional exponent, consisting of a plus or minus sign (@samp{+} or
-@samp{-}) followed by one or more base-30 digits.
-
-@item
-A forward slash (@samp{/}).
-@end itemize
-
-Integer fields take a form identical to floating-point fields, but they
-may not contain a fraction.
-
-String fields take the form of a integer field having value @var{n},
-followed by exactly @var{n} characters, which are the string content.
-
-@node Portable File Header, Version and Date Info Record, Portable File Structure, Portable File Format
-@section Portable File Header
-
-Every portable file begins with a 464-byte header, consisting of a
-200-byte collection of vanity splash strings, followed by a 256-byte
-character set translation table, followed by an 8-byte tag string.
-
-The 200-byte segment is divided into five 40-byte sections, each of
-which represents the string @code{@var{charset} SPSS PORT FILE} in a
-different character set encoding, where @var{charset} is the name of
-the character set used in the file, e.g.@: @code{ASCII} or
-@code{EBCDIC}. Each string is padded on the right with spaces in its
-respective character set.
-
-It appears that these strings exist only to inform those who might view
-the file on a screen, and that they are not parsed by SPSS products.
-Thus, they can be safely ignored. For those interested, the strings are
-supposed to be in the following character sets, in the specified order:
-EBCDIC, 7-bit ASCII, CDC 6-bit ASCII, 6-bit ASCII, Honeywell 6-bit
-ASCII.
-
-The 256-byte segment describes a mapping from the character set used in
-the portable file to an arbitrary character set having characters at the
-following positions:
-
-@table @asis
-@item 0--60
-
-Control characters. Not important enough to describe in full here.
-
-@item 61--63
-
-Reserved.
-
-@item 64--73
-
-Digits @samp{0} through @samp{9}.
-
-@item 74--99
-
-Capital letters @samp{A} through @samp{Z}.
-
-@item 100--125
-
-Lowercase letters @samp{a} through @samp{z}.
-
-@item 126
-
-Space.
-
-@item 127--130
-
-Symbols @code{.<(+}
-
-@item 131
-
-Solid vertical pipe.
-
-@item 132--142
-
-Symbols @code{&[]!$*);^-/}
-
-@item 143
-
-Broken vertical pipe.
-
-@item 144--150
-
-Symbols @code{,%_>}?@code{`:} @c @code{?} is an inverted question mark
-
-@item 151
-
-British pound symbol.
-
-@item 152--155
-
-Symbols @code{@@'="}.
-
-@item 156
-
-Less than or equal symbol.
-
-@item 157
-
-Empty box.
-
-@item 158
-
-Plus or minus.
-
-@item 159
-
-Filled box.
-
-@item 160
-
-Degree symbol.
-
-@item 161
-
-Dagger.
-
-@item 162
-
-Symbol @samp{~}.
-
-@item 163
-
-En dash.
-
-@item 164
-
-Lower left corner box draw.
-
-@item 165
-
-Upper left corner box draw.
-
-@item 166
-
-Greater than or equal symbol.
-
-@item 167--176
-
-Superscript @samp{0} through @samp{9}.
-
-@item 177
-
-Lower right corner box draw.
-
-@item 178
-
-Upper right corner box draw.
-
-@item 179
-
-Not equal symbol.
-
-@item 180
-
-Em dash.
-
-@item 181
-
-Superscript @samp{(}.
-
-@item 182
-
-Superscript @samp{)}.
-
-@item 183
-
-Horizontal dagger (?).
-
-@item 184--186
-
-Symbols @samp{@{@}\}.
-@item 187
-
-Cents symbol.
-
-@item 188
-
-Centered dot, or bullet.
-
-@item 189--255
-
-Reserved.
-@end table
-
-Symbols that are not defined in a particular character set are set to
-the same value as symbol 64; i.e., to @samp{0}.
-
-The 8-byte tag string consists of the exact characters @code{SPSSPORT}
-in the portable file's character set, which can be used to verify that
-the file is indeed a portable file.
-
-@node Version and Date Info Record, Identification Records, Portable File Header, Portable File Format
-@section Version and Date Info Record
-
-This record does not have a tag code. It has the following structure:
-
-@itemize @bullet
-@item
-A single character identifying the file format version. The letter A
-represents version 0, and so on.
-
-@item
-An 8-character string field giving the file creation date in the format
-YYYYMMDD.
-
-@item
-A 6-character string field giving the file creation time in the format
-HHMMSS.
-@end itemize
-
-@node Identification Records, Variable Count Record, Version and Date Info Record, Portable File Format
-@section Identification Records
-
-The product identification record has tag code @samp{1}. It consists of
-a single string field giving the name of the product that wrote the
-portable file.
-
-The subproduct identification record has tag code @samp{3}. It
-consists of a single string field giving additional information on the
-product that wrote the portable file.
-
-@node Variable Count Record, Case Weight Variable Record, Identification Records, Portable File Format
-@section Variable Count Record
-
-The variable count record has tag code @samp{4}. It consists of two
-integer fields. The first contains the number of variables in the file
-dictionary. The purpose of the second is unknown; it contains the value
-161 in all portable files examined so far.
-
-@node Case Weight Variable Record, Variable Records, Variable Count Record, Portable File Format
-@section Case Weight Variable Record
-
-The case weight variable record is optional. If it is present, it
-indicates the variable used for weighting cases; if it is absent,
-cases are unweighted. It has tag code @samp{6}. It consists of a
-single string field that names the weighting variable.
-
-@node Variable Records, Value Label Records, Case Weight Variable Record, Portable File Format
-@section Variable Records
-
-Each variable record represents a single variable. Variable records
-have tag code @samp{7}. They have the following structure:
-
-@itemize @bullet
-
-@item
-Width (integer). This is 0 for a numeric variable, and a number between 1
-and 255 for a string variable.
-
-@item
-Name (string). 1--8 characters long. Must be in all capitals.
-
-@item
-Print format. This is a set of three integer fields:
-
-@itemize @minus
-
-@item
-Format type (@pxref{Variable Record}).
-
-@item
-Format width. 1--40.
-
-@item
-Number of decimal places. 1--40.
-@end itemize
-
-@item
-Write format. Same structure as the print format described above.
-@end itemize
-
-Each variable record can optionally be followed by a missing value
-record, which has tag code @samp{8}. A missing value record has one
-field, the missing value itself (a floating-point or string, as
-appropriate). Up to three of these missing value records can be used.
-
-There is also a record for missing value ranges, which has tag code
-@samp{B}. It is followed by two fields representing the range, which
-are floating-point or string as appropriate. If a missing value range
-is present, it may be followed by a single missing value record.
-
-Tag codes @samp{9} and @samp{A} represent @code{LO THRU @var{x}} and
-@code{@var{x} THRU HI} ranges, respectively. Each is followed by a
-single field representing @var{x}. If one of the ranges is present, it
-may be followed by a single missing value record.
-
-In addition, each variable record can optionally be followed by a
-variable label record, which has tag code @samp{C}. A variable label
-record has one field, the variable label itself (string).
-
-@node Value Label Records, Portable File Data, Variable Records, Portable File Format
-@section Value Label Records
-
-Value label records have tag code @samp{D}. They have the following
-format:
-
-@itemize @bullet
-@item
-Variable count (integer).
-
-@item
-List of variables (strings). The variable count specifies the number in
-the list. Variables are specified by their names. All variables must
-be of the same type (numeric or string).
-
-@item
-Label count (integer).
-
-@item
-List of (value, label) tuples. The label count specifies the number of
-tuples. Each tuple consists of a value, which is numeric or string as
-appropriate to the variables, followed by a label (string).
-@end itemize
-
-@node Portable File Data, , Value Label Records, Portable File Format
-@section Portable File Data
-
-The data record has tag code @samp{F}. There is only one tag for all
-the data; thus, all the data must follow the dictionary. The data is
-terminated by the end-of-file marker @samp{Z}, which is not valid as the
-beginning of a data element.
-
-Data elements are output in the same order as the variable records
-describing them. String variables are output as string fields, and
-numeric variables are output as floating-point fields.
-
-@node q2c Input Format, Bugs, Portable File Format, Top
-@chapter @code{q2c} Input Format
-
-PSPP statistical procedures have a bizarre and somewhat irregular
-syntax. Despite this, a parser generator has been written that
-adequately addresses many of the possibilities and tries to provide
-hooks for the exceptional cases. This parser generator is named
-@code{q2c}.
-
-@menu
-* Invoking q2c:: q2c command-line syntax.
-* q2c Input Structure:: High-level layout of the input file.
-* Grammar Rules:: Syntax of the grammar rules.
-@end menu
-
-@node Invoking q2c, q2c Input Structure, q2c Input Format, q2c Input Format
-@section Invoking q2c
-
-@example
-q2c @var{input.q} @var{output.c}
-@end example
-
-@code{q2c} translates a @samp{.q} file into a @samp{.c} file. It takes
-exactly two command-line arguments, which are the input file name and
-output file name, respectively. @code{q2c} does not accept any
-command-line options.
-
-@node q2c Input Structure, Grammar Rules, Invoking q2c, q2c Input Format
-@section @code{q2c} Input Structure
-
-@code{q2c} input files are divided into two sections: the grammar rules
-and the supporting code. The @dfn{grammar rules}, which make up the
-first part of the input, are used to define the syntax of the
-statistical procedure to be parsed. The @dfn{supporting code},
-following the grammar rules, are copied largely unchanged to the output
-file, except for certain escapes.
-
-The most important lines in the grammar rules are used for defining
-procedure syntax. These lines can be prefixed with a dollar sign
-(@samp{$}), which prevents Emacs' CC-mode from munging them. Besides
-this, a bang (@samp{!}) at the beginning of a line causes the line,
-minus the bang, to be written verbatim to the output file (useful for
-comments). As a third special case, any line that begins with the exact
-characters @code{/* *INDENT} is ignored and not written to the output.
-This allows @code{.q} files to be processed through @code{indent}
-without being munged.
-
-The syntax of the grammar rules themselves is given in the following
-sections.
-
-The supporting code is passed into the output file largely unchanged.
-However, the following escapes are supported. Each escape must appear
-on a line by itself.
-
-@table @code
-@item /* (header) */
-
-Expands to a series of C @code{#include} directives which include the
-headers that are required for the parser generated by @code{q2c}.
-
-@item /* (decls @var{scope}) */
-
-Expands to C variable and data type declarations for the variables and
-@code{enum}s input and output by the @code{q2c} parser. @var{scope}
-must be either @code{local} or @code{global}. @code{local} causes the
-declarations to be output as function locals. @code{global} causes them
-to be declared as @code{static} module variables; thus, @code{global} is
-a bit of a misnomer.
-
-@item /* (parser) */
-
-Expands to the entire parser. Must be enclosed within a C function.
-
-@item /* (free) */
-
-Expands to a set of calls to the @code{free} function for variables
-declared by the parser. Only needs to be invoked if subcommands of type
-@code{string} are used in the grammar rules.
-@end table
-
-@node Grammar Rules, , q2c Input Structure, q2c Input Format
-@section Grammar Rules
-
-The grammar rules describe the format of the syntax that the parser
-generated by @code{q2c} will understand. The way that the grammar rules
-are included in @code{q2c} input file are described above.
-
-The grammar rules are divided into tokens of the following types:
-
-@table @asis
-@item Identifier (@code{ID})
-
-An identifier token is a sequence of letters, digits, and underscores
-(@samp{_}). Identifiers are @emph{not} case-sensitive.
-
-@item String (@code{STRING})
-
-String tokens are initiated by a double-quote character (@samp{"}) and
-consist of all the characters between that double quote and the next
-double quote, which must be on the same line as the first. Within a
-string, a backslash can be used as a ``literal escape''. The only
-reasons to use a literal escape are to include a double quote or a
-backslash within a string.
-
-@item Special character
-
-Other characters, other than whitespace, constitute tokens in
-themselves.
-
-@end table
-
-The syntax of the grammar rules is as follows:
-
-@example
-grammar-rules ::= ID : subcommands .
-subcommands ::= subcommand
- ::= subcommands ; subcommand
-@end example
-
-The syntax begins with an ID or STRING token that gives the name of the
-procedure to be parsed. The rest of the syntax consists of subcommands
-separated by semicolons (@samp{;}) and terminated with a full stop
-(@samp{.}).
-
-@example
-subcommand ::= sbc-options ID sbc-defn
-sbc-options ::=
- ::= sbc-option
- ::= sbc-options sbc-options
-sbc-option ::= *
- ::= +
-sbc-defn ::= opt-prefix = specifiers
- ::= [ ID ] = array-sbc
- ::= opt-prefix = sbc-special-form
-opt-prefix ::=
- ::= ( ID )
-@end example
-
-Each subcommand can be prefixed with one or more option characters. An
-asterisk (@samp{*}) is used to indicate the default subcommand; the
-keyword used for the default subcommand can be omitted in the PSPP
-syntax file. A plus sign (@samp{+}) is used to indicate that a
-subcommand can appear more than once; if it is not present then that
-subcommand can appear no more than once.
-
-The subcommand name appears after the option characters.
-
-There are three forms of subcommands. The first and most common form
-simply gives an equals sign (@samp{=}) and a list of specifiers, which
-can each be set to a single setting. The second form declares an array,
-which is a set of flags that can be individually turned on by the user.
-There are also several special forms that do not take a list of
-specifiers.
-
-Arrays require an additional @code{ID} argument. This is used as a
-prefix, prepended to the variable names constructed from the
-specifiers. The other forms also allow an optional prefix to be
-specified.
-
-@example
-array-sbc ::= alternatives
- ::= array-sbc , alternatives
-alternatives ::= ID
- ::= alternatives | ID
-@end example
-
-An array subcommand is a set of Boolean values that can independently be
-turned on by the user, listed separated by commas (@samp{,}). If an value has more
-than one name then these names are separated by pipes (@samp{|}).
-
-@example
-specifiers ::= specifier
- ::= specifiers , specifier
-specifier ::= opt-id : settings
-opt-id ::=
- ::= ID
-@end example
-
-Ordinary subcommands (other than arrays and special forms) require a
-list of specifiers. Each specifier has an optional name and a list of
-settings. If the name is given then a correspondingly named variable
-will be used to store the user's choice of setting. If no name is given
-then there is no way to tell which setting the user picked; in this case
-the settings should probably have values attached.
-
-@example
-settings ::= setting
- ::= settings / setting
-setting ::= setting-options ID setting-value
-setting-options ::=
- ::= *
- ::= !
- ::= * !
-@end example
-
-Individual settings are separated by forward slashes (@samp{/}). Each
-setting can be as little as an @code{ID} token, but options and values
-can optionally be included. The @samp{*} option means that, for this
-setting, the @code{ID} can be omitted. The @samp{!} option means that
-this option is the default for its specifier.
-
-@example
-setting-value ::=
- ::= ( setting-value-2 )
- ::= setting-value-2
-setting-value-2 ::= setting-value-options setting-value-type : ID
- setting-value-restriction
-setting-value-options ::=
- ::= *
-setting-value-type ::= N
- ::= D
-setting-value-restriction ::=
- ::= , STRING
-@end example
-
-Settings may have values. If the value must be enclosed in parentheses,
-then enclose the value declaration in parentheses. Declare the setting
-type as @samp{n} or @samp{d} for integer or floating point type,
-respectively. The given @code{ID} is used to construct a variable name.
-If option @samp{*} is given, then the value is optional; otherwise it
-must be specified whenever the corresponding setting is specified. A
-``restriction'' can also be specified which is a string giving a C
-expression limiting the valid range of the value. The special escape
-@code{%s} should be used within the restriction to refer to the
-setting's value variable.
-
-@example
-sbc-special-form ::= VAR
- ::= VARLIST varlist-options
- ::= INTEGER opt-list
- ::= DOUBLE opt-list
- ::= PINT
- ::= STRING @r{(the literal word STRING)} string-options
- ::= CUSTOM
-varlist-options ::=
- ::= ( STRING )
-opt-list ::=
- ::= LIST
-string-options ::=
- ::= ( STRING STRING )
-@end example
-
-The special forms are of the following types:
-
-@table @code
-@item VAR
-
-A single variable name.
-
-@item VARLIST
-
-A list of variables. If given, the string can be used to provide
-@code{PV_@var{*}} options to the call to @code{parse_variables}.
-
-@item INTEGER
-
-A single integer value.
-
-@item INTEGER LIST
-
-A list of integers separated by spaces or commas.
-
-@item DOUBLE
-
-A single floating-point value.
-
-@item DOUBLE LIST
-
-A list of floating-point values.
-
-@item PINT
-
-A single positive integer value.
-
-@item STRING
-
-A string value. If the options are given then the first string is an
-expression giving a restriction on the value of the string; the second
-string is an error message to display when the restriction is violated.
-
-@item CUSTOM
-
-A custom function is used to parse this subcommand. The function must
-have prototype @code{int custom_@var{name} (void)}. It should return 0
-on failure (when it has already issued an appropriate diagnostic), 1 on
-success, or 2 if it fails and the calling function should issue a syntax
-error on behalf of the custom handler.
-
-@end table
-
-@node Bugs, Function Index, q2c Input Format, Top
-@chapter Bugs
-
-@menu
-* Known bugs:: Pointers to other files.
-* Contacting the Author:: Where to send the bug reports.
-@end menu
-
-@node Known bugs, Contacting the Author, Bugs, Bugs
-@section Known bugs
-
-This is the list of known bugs in PSPP. In addition, @xref{Not
-Implemented}, and @xref{Functions Not Implemented}, for lists of bugs
-due to features not implemented. For known bugs in individual language
-features, see the documentation for that feature.
-
-@itemize @bullet
-@item
-Nothing has yet been tested exhaustively. Be cautious using PSPP to
-make important decisions.
-
-@item
-@code{make check} fails on some systems that don't like the syntax. I'm
-not sure why. If someone could make an attempt to track this down, it
-would be appreciated.
-
-@item
-PostScript driver bugs:
-
-@itemize @minus
-@item
-Does not support driver arguments `max-fonts-simult' or
-`optimize-text-size'.
-
-@item
-Minor problems with font-encodings.
-
-@item
-Fails to align fonts along their baselines.
-
-@item
-Does not support certain bizarre line intersections--should
-never crop up in practice.
-
-@item
-Does not gracefully substitute for existing fonts whose
-encodings are missing.
-
-@item
-Does not perform italic correction or left italic correction
-on font changes.
-
-@item
-Encapsulated PostScript is unimplemented.
-@end itemize
-
-@item
-ASCII driver bugs:
-
-@itemize @minus
-Does not support `infinite length' or `infinite width' paper.
-@end itemize
-@end itemize
-
-See below for information on reporting bugs not listed here.
-
-@node Contacting the Author, , Known bugs, Bugs
-@section Contacting the Author
-
-The author can be contacted at e-mail address
-@ifinfo
-<blp@@gnu.org>.
-@end ifinfo
-@iftex
-@code{<blp@@gnu.org>}.
-@end iftex
-
-PSPP bug reports should be sent to
-@ifinfo
-<bug-gnu-pspp@@gnu.org>.
-@end ifinfo
-@iftex
-@code{<bug-gnu-pspp@@gnu.org>}.
-@end iftex
-
-@node Function Index, Concept Index, Bugs, Top
-@chapter Function Index
-@printindex fn
-
-@node Concept Index, Command Index, Function Index, Top
-@chapter Concept Index
-@printindex cp
-
-@node Command Index, , Concept Index, Top
-@chapter Command Index
-@printindex vr
-
-@contents
-@bye
-
-@c Local Variables:
-@c compile-command: "makeinfo pspp.texi"
-@c End:
projects / pspp-builds.git / commitdiff