work on docs

[pspp] / doc / data-io.texi

diff --git a/doc/data-io.texi b/doc/data-io.texi
index 1316f603a6aa9d8c0ee832d460817ba645531570..9f5b8dfbeec3303c19ffe29b89249d96e8c2a67f 100644 (file)
--- a/doc/data-io.texi
+++ b/doc/data-io.texi
@@ -1,3 +1,12 @@
+@c PSPP - a program for statistical analysis.
+@c Copyright (C) 2017, 2020 Free Software Foundation, Inc.
+@c Permission is granted to copy, distribute and/or modify this document
+@c under the terms of the GNU Free Documentation License, Version 1.3
+@c or any later version published by the Free Software Foundation;
+@c with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
+@c A copy of the license is included in the section entitled "GNU
+@c Free Documentation License".
+@c

 @c (modify-syntax-entry ?_ "w")
 @c (modify-syntax-entry ?' "'")
 @c (modify-syntax-entry ?@ "'")
 @c (modify-syntax-entry ?_ "w")
 @c (modify-syntax-entry ?' "'")
 @c (modify-syntax-entry ?@ "'")


@@ -11,7 +20,7 @@
 @cindex cases
 @cindex observations
 
 @cindex cases
 @cindex observations
 

-Data are the focus of the @pspp{} language.  
+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,
 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,


@@ -180,7 +189,7 @@ The DATASET DECLARE command creates a new dataset that is initially
 ``empty,'' that is, it has no dictionary or data.  If a dataset with
 the given name already exists, this has no effect.  The new dataset
 can be used with commands that support output to a dataset,
 ``empty,'' that is, it has no dictionary or data.  If a dataset with
 the given name already exists, this has no effect.  The new dataset
 can be used with commands that support output to a dataset,

-e.g. AGGREGATE (@pxref{AGGREGATE}).
+@i{e.g.} AGGREGATE (@pxref{AGGREGATE}).

 
 @vindex DATASET CLOSE
 The DATASET CLOSE command deletes a dataset.  If the active dataset is
 
 @vindex DATASET CLOSE
 The DATASET CLOSE command deletes a dataset.  If the active dataset is


@@ -295,7 +304,7 @@ the beginning of an input file.  It can be used to skip over a row
 that contains variable names, for example.
 
 @cmd{DATA LIST} can optionally output a table describing how the data file
 that contains variable names, for example.
 
 @cmd{DATA LIST} can optionally output a table describing how the data file

-will be read.  The @subcmd{TABLE} subcommand enables this output, and
+is read.  The @subcmd{TABLE} subcommand enables this output, and

 @subcmd{NOTABLE} disables it.  The default is to output the table.
 
 The list of variables to be read from the data list must come last.
 @subcmd{NOTABLE} disables it.  The default is to output the table.
 
 The list of variables to be read from the data list must come last.


@@ -319,7 +328,7 @@ changed; see @ref{SET} for more information.)
 
 In columnar style, to use a variable format other than the default,
 specify the format type in parentheses after the column numbers.  For
 
 In columnar 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)}.  
+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
 
 In addition, implied decimal places can be specified in parentheses
 after the column numbers.  As an example, suppose that a data file has a


@@ -375,7 +384,7 @@ FORTRAN and columnar styles may be freely intermixed.  Columnar 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 columnar specifiers.
 leaves the active column immediately after the ending column
 specified.  Record motion using @code{NEWREC} in FORTRAN style also
 applies to later FORTRAN and columnar specifiers.

- 
+

 @menu
 * DATA LIST FIXED Examples::    Examples of DATA LIST FIXED.
 @end menu
 @menu
 * DATA LIST FIXED Examples::    Examples of DATA LIST FIXED.
 @end menu


@@ -475,7 +484,7 @@ DATA LIST FREE
         [(@{TAB,'@var{c}'@}, @dots{})]
         [@{NOTABLE,TABLE@}]
         [FILE='@var{file_name}' [ENCODING='@var{encoding}']]
         [(@{TAB,'@var{c}'@}, @dots{})]
         [@{NOTABLE,TABLE@}]
         [FILE='@var{file_name}' [ENCODING='@var{encoding}']]

-        [SKIP=@var{record_cnt}]
+        [SKIP=@var{n_records}]

         /@var{var_spec}@dots{}
 
 where each @var{var_spec} takes one of the forms
         /@var{var_spec}@dots{}
 
 where each @var{var_spec} takes one of the forms


@@ -484,7 +493,10 @@ where each @var{var_spec} takes one of the forms
 @end display
 
 In free format, the input data is, by default, structured as a series
 @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
+of fields separated by spaces, tabs, or line breaks.
+If the current @subcmd{DECIMAL} separator is @subcmd{DOT} (@pxref{SET}),
+then commas are also treated as field separators.
+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
 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


@@ -511,7 +523,7 @@ 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 and Output Formats}).  Format specifications apply to all
 This list must be introduced by a single slash (@samp{/}).  The set of
 variable names may contain format specifications in parentheses
 (@pxref{Input and Output Formats}).  Format specifications apply to all

-variables back to the previous parenthesized format specification.  
+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}.
 
 In addition, an asterisk may be used to indicate that all variables
 preceding it are to have input/output format @samp{F8.0}.


@@ -743,7 +755,7 @@ For reading text files in CHARACTER mode, all of the forms described
 for ENCODING on the INSERT command are supported (@pxref{INSERT}).
 For reading in other file-based modes, encoding autodetection is not
 supported; if the specified encoding requests autodetection then the
 for ENCODING on the INSERT command are supported (@pxref{INSERT}).
 For reading in other file-based modes, encoding autodetection is not
 supported; if the specified encoding requests autodetection then the

-default encoding will be used.  This is also true when a file handle
+default encoding is used.  This is also true when a file handle

 is used for writing a file in any mode.
 
 @node INPUT PROGRAM
 is used for writing a file in any mode.
 
 @node INPUT PROGRAM


@@ -798,118 +810,115 @@ structure.
 @cmd{INPUT PROGRAM} must contain at least one @cmd{DATA LIST} or
 @cmd{END FILE} command.
 
 @cmd{INPUT PROGRAM} must contain at least one @cmd{DATA LIST} or
 @cmd{END FILE} command.
 

-All this is very confusing.  A few examples should help to clarify.
+@subheading Example 1: Read two files in parallel to the end of the shorter
+
+The following example reads variable X from file @file{a.txt} and
+variable Y from file @file{b.txt}.  If one file is shorter than the
+other then the extra data in the longer file is ignored.

 
 

-@c If you change this example, change the regression test1 in
-@c tests/command/input-program.sh to match.

 @example
 INPUT PROGRAM.
 @example
 INPUT PROGRAM.

-        DATA LIST NOTABLE FILE='a.data'/X 1-10.
-        DATA LIST NOTABLE FILE='b.data'/Y 1-10.
+    DATA LIST NOTABLE FILE='a.txt'/X 1-10.
+    DATA LIST NOTABLE FILE='b.txt'/Y 1-10.

 END INPUT PROGRAM.
 LIST.
 @end example
 
 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.
+@subheading Example 2: Read two files in parallel, supplementing the shorter
+
+The following example also reads variable X from @file{a.txt} and
+variable Y from @file{b.txt}.  If one file is shorter than the other
+then it continues reading the longer to its end, setting the other
+variable to system-missing.

 
 

-@c If you change this example, change the regression test2 in
-@c tests/command/input-program.sh to match.

 @example
 INPUT PROGRAM.
 @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.
+    NUMERIC #A #B.
+
+    DO IF NOT #A.
+        DATA LIST NOTABLE END=#A FILE='a.txt'/X 1-10.
+    END IF.
+    DO IF NOT #B.
+        DATA LIST NOTABLE END=#B FILE='b.txt'/Y 1-10.
+    END IF.
+    DO IF #A AND #B.
+        END FILE.
+    END IF.
+    END CASE.

 END INPUT PROGRAM.
 LIST.
 @end example
 
 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.
+@subheading Example 3: Concatenate two files (version 1)
+
+The following example reads data from file @file{a.txt}, then from
+@file{b.txt}, and concatenates them into a single active dataset.

 
 

-@c If you change this example, change the regression test3 in
-@c tests/command/input-program.sh to match.

 @example
 INPUT PROGRAM.
 @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.
+    NUMERIC #A #B.
+
+    DO IF #A.
+        DATA LIST NOTABLE END=#B FILE='b.txt'/X 1-10.
+        DO IF #B.
+            END FILE.

         ELSE.
         ELSE.

-                DATA LIST NOTABLE END=#A FILE='a.data'/X 1-10.
-                DO IF NOT #A.
-                        END CASE.
-                END IF.
+            END CASE.
+        END IF.
+    ELSE.
+        DATA LIST NOTABLE END=#A FILE='a.txt'/X 1-10.
+        DO IF NOT #A.
+            END CASE.

         END IF.
         END IF.

+    END IF.

 END INPUT PROGRAM.
 LIST.
 @end example
 
 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 dataset.
+@subheading Example 4: Concatenate two files (version 2)
+
+This is another way to do the same thing as Example 3.

 
 

-@c If you change this example, change the regression test4 in
-@c tests/command/input-program.sh to match.

 @example
 INPUT PROGRAM.
 @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.
+    NUMERIC #EOF.

 
 

-        END FILE.
+    LOOP IF NOT #EOF.
+        DATA LIST NOTABLE END=#EOF FILE='a.txt'/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.txt'/X 1-10.
+        DO IF NOT #EOF.
+            END CASE.
+        END IF.
+    END LOOP.
+
+    END FILE.

 END INPUT PROGRAM.
 LIST.
 @end example
 
 END INPUT PROGRAM.
 LIST.
 @end example
 

-The above example does the same thing as the previous example, in a
-different way.
+@subheading Example 5: Generate random variates
+
+The follows example creates a dataset that consists of 50 random
+variates between 0 and 10.

 
 

-@c If you change this example, make similar changes to the regression
-@c test5 in tests/command/input-program.sh.

 @example
 INPUT PROGRAM.
 @example
 INPUT PROGRAM.

-        LOOP #I=1 TO 50.
-                COMPUTE X=UNIFORM(10).
-                END CASE.
-        END LOOP.
-        END FILE.
+    LOOP #I=1 TO 50.
+        COMPUTE X=UNIFORM(10).
+        END CASE.
+    END LOOP.
+    END FILE.

 END INPUT PROGRAM.
 END INPUT PROGRAM.

-LIST/FORMAT=NUMBERED.
+LIST /FORMAT=NUMBERED.

 @end example
 
 @end example
 

-The above example causes an active dataset to be created consisting of 50
-random variates between 0 and 10.
-

 @node LIST
 @section LIST
 @vindex LIST
 @node LIST
 @section LIST
 @vindex LIST


@@ -942,10 +951,6 @@ currently not used.
 Case numbers start from 1.  They are counted after all transformations
 have been considered.
 
 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 NEW FILE
 @cmd{LIST} is a procedure.  It causes the data to be read.
 
 @node NEW FILE


@@ -964,7 +969,7 @@ active dataset.
 @vindex PRINT
 
 @display
 @vindex PRINT
 
 @display

-PRINT 
+PRINT

         [OUTFILE='@var{file_name}']
         [RECORDS=@var{n_lines}]
         [@{NOTABLE,TABLE@}]
         [OUTFILE='@var{file_name}']
         [RECORDS=@var{n_lines}]
         [@{NOTABLE,TABLE@}]


@@ -988,10 +993,11 @@ are specified, @cmd{PRINT} outputs a single blank line.
 
 The @subcmd{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
 
 The @subcmd{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

-Handles}).  If @subcmd{OUTFILE} is not present then output will be sent to
-@pspp{}'s output listing file.  When @subcmd{OUTFILE} is present, a space is
-inserted at beginning of each output line, even lines that otherwise
-would be blank.
+Handles}).  If @subcmd{OUTFILE} is not present then output is sent to
+@pspp{}'s output listing file.  When @subcmd{OUTFILE} is present, the
+output is written to @var{file_name} in a plain text format, with a
+space inserted at beginning of each output line, even lines that
+otherwise would be blank.

 
 The @subcmd{ENCODING} subcommand may only be used if the
 @subcmd{OUTFILE} subcommand is also used.  It specifies the character
 
 The @subcmd{ENCODING} subcommand may only be used if the
 @subcmd{OUTFILE} subcommand is also used.  It specifies the character


@@ -1007,15 +1013,15 @@ 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
 
 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
+indicating which output line is specified.  In the absence of this
+line number, the next line number is 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, specifying
 the column on the line where the string should start.  Otherwise, the
 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, specifying
 the column on the line where the string should start.  Otherwise, the

-string will be printed at the current position on the line.
+string is 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
 
 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


@@ -1023,10 +1029,10 @@ 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
 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.
+is interpreted in the same way.

 
 If a FORTRAN type specification is used to move backwards on the current
 
 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
+line, then text is written at that point on the line, the line is

 truncated to that length, although additional text being added will
 again extend the line to that length.
 
 truncated to that length, although additional text being added will
 again extend the line to that length.
 


@@ -1035,7 +1041,7 @@ again extend the line to that length.
 @vindex PRINT EJECT
 
 @display
 @vindex PRINT EJECT
 
 @display

-PRINT EJECT 
+PRINT EJECT

         OUTFILE='@var{file_name}'
         RECORDS=@var{n_lines}
         @{NOTABLE,TABLE@}
         OUTFILE='@var{file_name}'
         RECORDS=@var{n_lines}
         @{NOTABLE,TABLE@}


@@ -1077,7 +1083,7 @@ PRINT SPACE [OUTFILE='file_name'] [ENCODING='@var{encoding}'] [n_lines].
 
 The @subcmd{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
 
 The @subcmd{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

-Handles}).  If OUTFILE is not specified then output will be directed to
+Handles}).  If OUTFILE is not specified then output is directed to

 the listing file.
 
 The @subcmd{ENCODING} subcommand may only be used if @subcmd{OUTFILE}
 the listing file.
 
 The @subcmd{ENCODING} subcommand may only be used if @subcmd{OUTFILE}


@@ -1104,7 +1110,7 @@ for further processing.
 The @subcmd{FILE} subcommand, which is optional, is used to specify the file to
 have its line re-read.  The file must be specified as the name of a file
 handle (@pxref{File Handles}).  If FILE is not specified then the last
 The @subcmd{FILE} subcommand, which is optional, is used to specify the file to
 have its line re-read.  The file must be specified as the name of a file
 handle (@pxref{File Handles}).  If FILE is not specified then the last

-file specified on @cmd{DATA LIST} will be assumed (last file specified
+file specified on @cmd{DATA LIST} is 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
 lexically, not in terms of flow-of-control).
 
 By default, the line re-read is re-read in its entirety.  With the


@@ -1207,7 +1213,7 @@ structure (@pxref{LOOP}).  Use @cmd{DATA LIST} before, not after,
 @vindex WRITE
 
 @display
 @vindex WRITE
 
 @display

-WRITE 
+WRITE

         OUTFILE='@var{file_name}'
         RECORDS=@var{n_lines}
         @{NOTABLE,TABLE@}
         OUTFILE='@var{file_name}'
         RECORDS=@var{n_lines}
         @{NOTABLE,TABLE@}


@@ -1220,7 +1226,7 @@ WRITE
         @var{var_list} *
 @end display
 
         @var{var_list} *
 @end display
 

-@code{WRITE} writes text or binary data to an output file.  
+@code{WRITE} writes text or binary data to an output file.

 
 @xref{PRINT}, for more information on syntax and usage.  @cmd{PRINT}
 and @cmd{WRITE} differ in only a few ways:
 
 @xref{PRINT}, for more information on syntax and usage.  @cmd{PRINT}
 and @cmd{WRITE} differ in only a few ways: