Re-implement MEANS.

[pspp] / NEWS

PSPP NEWS -- history of user-visible changes.
Copyright (C) 1996-2000, 2008-2016, 2017, 2019 Free Software Foundation, Inc.
See the end for copying conditions.

Please send PSPP bug reports to bug-gnu-pspp@gnu.org.

Changes from 1.2.0 to 1.3.0:

 * FREQUENCIES will emit a warning if one or more weight values are missing.

 * Plain text output is no longer divided into pages, since it is now
   rarely printed on paper.

 * pspp-convert: New "-a", "-l", "--password-list" options to search
   for an encrypted file's password.

 * Improvements to SAVE DATA COLLECTION support for MDD files.

 * Bug fix for CVE-2018-20230.

 * The EXAMINE command will now perform the Shapiro-Wilk test when
   one or more plots are requested.

 * The REGRESSION command now supports the /STATISTICS=TOL option which
   outputs tolerance and variance inflation factor metrics for the data.

 * The QUICK CLUSTER command now supports the /SAVE option which can
   be used to save the cases' cluster membership and/or their distance
   from the cluster centre to the active file.

 * The MEANS command has been re-implemented.

 * A bug where the GUI would crash when T-TEST was executed whilst
   a filter was set has been fixed.

 * The GUI now has a sub-dialog for post-hoc tests of the oneway
   anova test.

 * GRAPH: Categorical barcharts displaying percentages now show the
   sub-category as a percentage of the primary category instead of the
   total.

Changes from 1.0.1 to 1.2.0:

 * New experimental command SAVE DATA COLLECTION to save MDD files.

 * MTIME and YMDHMS variable formats now supported.

 * Build changes:

   - zlib is now a required dependency.  (Previously it was optional.)

   - Gtk+3.18.0 or later must now be used when building.

   - The code implementing the sheet rendering has been removed.  Instead we
     use a third party library: spread-sheet-widget.

 * The "NOMISSING" keyword when generating syntax for piecharts in the
   frequencies command was omitted.  This has been corrected.

Changes from 1.0.0 to 1.0.1:

 * Bug fixes, including fixes for CVE-2017-12958, CVE-2017-12959,
   CVE-2017-12960, and CVE-2017-12961.

Changes from 0.11.0 to 1.0.0:

 * Translation updates.

Changes from 0.10.2 to 0.11.0:

 * The REGRESSION command now has a /ORIGIN subcommand to perform
   regression through the origin.

 * The FACTOR command can now analyse matrix files prepared with MATRIX DATA.

 * The FACTOR command can now print the anti-image matrices.

 * The MATRIX DATA command has been added.

 * Some inappropriate properties in selection dialogs have been corrected.

 * A bug which could cause the HTML driver to go into a tight loop
   has been fixed.

 * An error in the FREQUENCIES procedure, where the word "Mean" was
   printed when "Variance" was appropriate has been fixed.

 * The ncurses library is no longer required or used.

 * A bug where the Mann-Whitney test would give misleading results
   if run on multiple variables and MISSING=ANALAYSIS was specified
   has been fixed.

 * Gtk+3.14.5 or later must now be used when building.

 * Graphical user interface changes:

 ** There is a new menu: Edit|Options

 ** The Non Parametric Statistics Menu has a new item: "K Independent Samples".

 ** Dialog boxes can now be canceled using the <Escape> key.

 * The AUTORECODE command now accepts an optional / before INTO.

 * The short form of the VECTOR command can now create string variables.

 * Bug fixes, including fixes for CVE-2017-10791 and CVE-2017-10792.

Changes from 0.10.1 to 0.10.2:

 * CROSSTABS implements a new COUNT subcommand to round case or cell
   weights.

 * Help will be opened as HTML in default browser if yelp
   is not available.

 * When plotting scatterplots with only one dataset (the simple case)
   the colour used for the dataset is now black.  The previous default
   from the Tango palette was too faint to see easily.

 * The varible info dialog could previously only paste a single variable.
   Now it can paste multiple variables.

 * Bug fixes, including the following:

   - T-test with independent samples GUI crashed with string
     type variable as group variable.

   - The variable info dialog showed the previous selected variable
     superimposed with the currently selected one.

   - The GLM command did not properly deal with missing values.  This
     has been fixed.

Changes from 0.10.0 to 0.10.1:

 * Bug fixes, including the following:

   - A bug where certain dialog boxes could not be properly populated
     has been fixed.

   - Various commands have been hardened against errors when called
     with invalid syntax.

 * Translation updates.  Thanks to our translators!

Changes from 0.8.5 to 0.10.0:

 * The QUICK CLUSTER command has a  /PRINT subcommand which shows
   the initial cluster centres and the final cluster membership of
   each case.  The clustering algorithm has also been updated, so
   as to produce better separated clusters.

 * A Russian localisation has been contributed.

 * The GRAPH command now has a /BAR subcommand to draw barcharts.

 * If the DECIMAL character is set to COMMA then the ',' character
   will not be treated as a separator by DATA LIST.

 * The graphical user interface (psppire) has been changed as follows:

   - It now uses Gtk+ version 3 instead of version 2.  Accordingly, it has a 
     somewhat different look and feel.

   - There is now a Graphs menu to access the GRAPH command.

   - The status of dialog box widgets are now preserved between calls
     to the same dialog box for the same dataset.

   - The dialog box for the Logistic Regression command will now
     infer that string variables or any varible with a "measure"
     of Nominal or Ordinal are to be treated as categorical variables
     and will generate syntax accordingly.

 * The pspp-convert utility can now decrypt encrypted syntax files.
   The encrypted syntax file format is unacceptably insecure, so to
   discourage its use PSPP and PSPPIRE do not directly read or write
   this format.

 * New commands:

   - SORT VARIABLES.

 * The following functions for transformation expressions are new:

   - REPLACE, for search-and-replace of one string with another.

   - STRUNC, to truncate a string and trim trailing spaces.

   - MEDIAN, to compute the median of its arguments.

   - The TRUNC function in expressions now supports additional arguments
     for truncating to values other than integers and to indicate a level
     of rounding fuzz.  The default rounding fuzz may now be controlled
     and displayed with SET FUZZBITS and SHOW FUZZBITS, respectively.

 * Bug fixes, including the following notable ones:

   - The correlation coefficient in the paired samples t-test
     procedure is now correctly calculated when presented with
     weighted data.

   - The ESCAPE subcommand has been removed from GET DATA /TYPE=TXT.
     For compatibility, the behavior that ESCAPE enabled is now the
     default and only supported behavior.

   - Rendering of the variable and data sheets in right-to-left locales
     now works properly.

   - The Mann-Whitney test, when run on a dataset containing values
     of the group variable, other than those defining the test groups,
     would incorrectly calculate the ranks.  This has been corrected.

 * The IMPORTCASES subcommand on GET DATA is now ignored, for
   compatibility.

Changes from 0.8.4 to 0.8.5:

 * The FREQUENCIES and CROSSTABS commands can now generate barcharts.

 * The FACTOR command can now perform PROMAX rotations.

 * SPSS/PC+ system files are now supported on GET and other commands
   that read SPSS system files.  The pspp-convert program can now read
   SPSS/PC+ system files.  Writing the obsolete SPSS/PC+ system file
   format is not supported.

 * SYSFILE INFO can now read SPSS/PC+ system files and SPSS portable
   files.

 * FREQUENCIES: A bug was fixed where an assertion failure occurred
   when an empty dataset was presented.

 * The GRAPH command is now available.  Initially it supports
   scatterplots and histograms.

 * The RND operator in expressions now supports additional operands
   for rounding to values other than integers and to indicate a level
   of rounding fuzz.  The default rounding fuzz may now be controlled
   and displayed with SET FUZZBITS and SHOW FUZZBITS, respectively.

Changes from 0.8.3 to 0.8.4:

 * Formatting of SYSFILE INFO output was made easier to read.

 * Bug fixes, including the following notable ones:

   - FREQUENCIES works properly for string variables.  (This bug was
     introduced in 0.8.2.)

   - CROSSTABS now correctly computes all of the measures that it
     offers.  Some measures have been removed because they were not
     computed correctly.

   - The NPAR TESTS calculation of significance for the RUNS
     subcommand has been corrected.

   - Planned comparisons in ONEWAY ANOVA now correctly handle negative
     T-values.

   - The COUNT command now correctly treats missing values as
     documented.

   - Conformance fixes to Open Document output format.

Changes from 0.8.2 to 0.8.3:

 * Independent T-Tests displayed the standard error of the difference
   and the confidence interval for the unequal variances case, where
   the equal variances case should have been.  This has been fixed.

 * REGRESSION now recognises /STATISTICS=CI(x) which causes confidence
   intervals for the coefficients to be printed.

 * When DESCRIPTIVES calculates Z scores, it now omits cases filtered
   by the current FILTER settings.

 * PSPPIRE graphical user interface improvements:

   - Dialog boxes with source  variable lists can now choose the sort
     order;  right click and select from the popup menu.

   - File|Open now allows an encoding to be selected for opening
     system files.

   - File|Display Data File Information|External File... now allows an
     encoding to be selected.

   - A problem with the Means dialog has been resolved (bug #41433).

   - Several problems related to the input of spreadsheets have been
     fixed (bug #41657, #41620

 * System file related improvements:

   - With ENCODING="DETECT", SYSFILE INFO can now help the user to
     pick an encoding for reading a system file that does not identify
     its own encoding

   - SYSFILE INFO now accepts an ENCODING subcommand to specify the
     character encoding of string data in the system file.

   - Variable labels over 255 bytes long are now accepted without
     truncation (bug #41863).

   - System files that contain duplicate variable names may now be
     read successfully (bug #41475).

Changes from 0.8.1 to 0.8.2:

 * Charts are now rendered with colours from the Tango palette instead
   of fully saturated primaries.

 * Support for new system file variants:

   - PSPP can now read and write ZCOMPRESSED system files, which
     compress data much more effectively than older "compressed"
     files.  (The older format is still supported.)

   - PSPP can now decrypt encrypted system files, using the new
     pspp-convert utility.  The encrypted system file format is
     unacceptably insecure, so to discourage its use PSPP and PSPPIRE
     do not directly read or write this format.

 * Missing values for long string variables are now read from and
   written to system files in an SPSS-compatible fashion.

   (Earlier versions of PSPP that supported missing values for long
   string variables wrote them to system files in an SPSS-incompatible
   way.  To fix the problem, read the system file with this version of
   PSPP and then save a new copy of it.)

 * pspp-convert, a new standalone utility for converting SPSS system
   and portable files to other formats, is now included.  The initial
   version supports comma-separated value files as output format.
   pspp-convert can also decrypt encrypted system files.

 * Build changes:

   - zlib is now a required dependency.  (Previously it was optional.)

Changes from 0.8.0 to 0.8.1:

 * New commands:

   - VARIABLE ROLE.

 * Changes to existing commands:

   - CROSSTABS: The requirement that one expected count must be less than five
        before Fishers Exact Test will be reported has been removed.

 * PSPPIRE graphical user interface improvements:

   - A new set of icons has been contributed.

   - Syntax windows now parse syntax in "auto" mode, which in practice
     should mean that both "batch" and "interactive" syntax now works,
     instead of just "interactive" syntax.

   - The variable pane of data windows now include a Role column.

 * Notable bug fixes:

   - System files written by IBM SPSS 21 are now read without warnings.

   - System files written by "VOXCO INTERVIEWER 4.3" are now read
     without warnings.

   - PSPPIRE should now more gracefully handle syntax files that contain
     errors.

Changes from 0.6.2 to 0.8.0:

 * New commands:

   - ADD FILES
   - CORRELATIONS
   - DATAFILE ATTRIBUTES
   - DATASET ACTIVATE
   - DATASET CLOSE
   - DATASET COPY
   - DATASET DECLARE
   - DATASET DISPLAY
   - DATASET NAME
   - LOGISTIC REGRESSION
   - MATCH FILES
   - MEANS
   - MRSETS
   - PRESERVE and RESTORE
   - QUICK CLUSTER
   - RELIABILITY
   - ROC
   - SAVE TRANSLATE to CSV and tab-delimited files
   - UPDATE
   - VARIABLE ATTRIBUTES

 * Changes to existing commands:

   - AUTORECODE has a new GROUP subcommand.

   - CROSSTABS has been re-implemented to fix numerous bugs.

   - EXAMINE: /MISSING=LISTWISE is now the default.

   - DO REPEAT command has been reimplemented.  Now, when DO REPEAT
     contains an INCLUDE or INSERT command, substitutions are not
     applied to the included file.
  
   - FILE HANDLE has a new ENDS subcommand to select CR or CRLF new-lines.

   - HOST has been updated to use more modern syntax.

   - Most commands that work with data files now support a new
     ENCODING subcommand.

   - MISSING VALUES can now assign missing values to long string
     variables.

   - ONEWAY: the POSTHOC subcommand is now implemented.

   - The following new subcommands to NPAR TESTS have been implemented:
     COCHRAN, FRIEDMAN, JONCKHEERE-TERPSTRA, KENDALL, KRUSKAL-WALLIS, MANN-WHITNEY, 
     MCNEMAR, SIGN, WILCOXON, and RUNS

   - SET and SHOW no longer have ENDCMD, NULLINE, PROMPT, CPROMPT, and
     DPROMPT subcommands.  The defaults are now fixed values.

   - SHOW now has a JOURNAL subcommand, to show the location of the
     journal file.

   - VALUE LABELS can now assign value labels to long string
     variables.

 * Other language changes:

   - The new DATASET commands replace the "scratch file" PSPP
     extension, which is no longer supported.

   - Strings may now include arbitrary Unicode code points specified
     in hexadecimal, using the syntax U'hhhh'.  For example, Unicode
     code point U+1D11E, the musical G clef character, may be
     expressed as U'1D11E'.

     See the "Tokens" section in the PSPP manual for more information.

   - In previous versions of PSPP, in a string expressed in
     hexadecimal with X'hh' syntax, the hexadecimal digits expressed
     bytes in the locale encoding.  In this version of PSPP, X'hh'
     syntax always expresses bytes in UTF-8 encoding.

     See the "Tokens" section in the PSPP manual for more information.

 * PSPPIRE graphical user interface improvements:

   - Added support for non-ASCII characters in strings, labels and
     variable names.

   - A "Split Window" function is available, which makes it easier to
     see different parts of a large data file.

   - Data files can now be opened by specifing their name as the first
     argument.  This means that on a properly configured desktop, double
     clicking on an icon will open the file.

   - Foreign formats, such as Gnumeric, OpenDocument and CSV can be imported
     via using an "intelligent" application assistant dialog.

 * Output changes:

   - The new "cairo" output driver supports output in PostScript, PDF,
     and SVG formats.  Its functionality is a superset of that of the
     "postscript" driver, which has been removed.  You must have Cairo
     and Pango installed to build the "cairo" driver.

   - Charts are now produced with Cairo and Pango, instead of libplot.
     Without them, the new graphing features will not work.  If you do
     not have Cairo and Pango installed, you must run `configure' with
     --without-cairo.

   - The plain text output driver now properly supports multibyte UTF-8
     characters, including double-width characters and combining
     accents.

   - Output to OpenDocument format is now supported.

   - The HTML output is much improved.

 * The "pspp" program has a new option --batch (or -b) that selects
   "batch" syntax mode.  In previous versions of PSPP this syntax mode
   was the default.  Now a new "auto" syntax mode is the default.  In
   "auto" mode, PSPP interprets most syntax files correctly regardless
   of their intended syntax mode.

   See the "Syntax Variants" section in the PSPP manual for more
   information.

 * The "pspp" program has a new option --syntax-encoding that
   specifies the encoding for syntax files listed on the command line,
   as well as the default encoding for syntax files included with
   INCLUDE or INSERT.  The default is to accept the system locale
   encoding, UTF-8, UTF-16, or UTF-32, automatically detecting which
   one the system file uses.

   See the documentation for the INSERT command in the PSPP manual for
   more information.

 * Text data files that PRINT and WRITE creates now use the system
   native line ends by default (CRLF on Windows, LF only elsewhere).
   Use the new ENDS subcommand on FILE HANDLE to override the default.

 * A new Perl module allows Perl programs to read and write PSPP
   system files.

 * A tutorial chapter has been added to the user manual.
\f
Changes from 0.6.1 to 0.6.2:

  * New translations:

    - Dutch, thanks to Harry Thijssen.

    - Brazilian Portuguese, thanks to Michel Boaventura.

    Thanks for translations are also due to the coordinators at
    translationproject.org.

  * Statistical bug fixes:

    - REGRESSION: Report correct standard error of the estimate (bug
      #25677).

    - T-TEST: Report correct significance of paired sample T-test in
      the common case (bug #26936) and corner cases.  Thanks to Mike
      Griffiths and Matej Cepl for reporting these bugs.

  * Build fixes and changes:

    - Fix build with GTK+ 2.17.4 and later.

    - Make running "make" after running "configure" with different
      settings reliably rebuild version.c.

    - Cygwin and MinGW build fixes.

    - Fixes for building with recent gnulib.

    - The Makefile now honors two new variables, PSPP_LDFLAGS and
      PSPPIRE_LDFLAGS, that affect linking of the PSPP and PSPPIRE
      binaries, respectively.  This makes building easier for some
      packagers.

    - Fixes for "configure --enable-relocatable" (bug #25508).

  * Data file bug fixes and changes:

    - Fix reading text data files that contain a mix of white space
      and commas.  Now "a ,b" is treated as two fields containing "a"
      and "b"; previously it was treated as three, with an empty field
      in the middle.

    - Fix writing corrupted .sav files on Windows.

    - Fix writing variable labels longer than 252 bytes to save files.
      Thanks to Robert Westlund for reporting this bug.

    - Fix writing corrupted .por files (bug #26034).

    - Fix reading .por files whose initial lines are not padded out
      with spaces as expected.

    - PSPP will no longer issue warnings about some .sav file records
      or values that it does not understand.  These warnings were
      harmless, but needlessly alarmed some users.

    - Fix crash reading empty string fields from PostgreSQL databases.

  * Bug fixes that affect PSPP and PSPPIRE:

    - Users may now control precision of output statistics.  Instead
      of hard coding the width and decimals of output numbers, respect
      the default format in most instances.  Counts are now normally
      displayed with the format of the weight variable, if any.

    - Fix crash when an INSERT command specifies the name of a file
      that does not exist (bug #24569).

    - Fix crash when CROSSTABS specifies a long-string variable (bugs
      #24557 and #26131).

    - Fix crash drawing pie charts with many segments.

    - Fix crash when NUMERIC specifies an invalid format.

  * PSPPIRE bug fixes and changes:

    - On Windows, write the output file to the user's home directory
      instead of the current directory, to better match user
      expectations.

    - Some data editor fixes.

  * Documentation:

    - Fix typo in BINOMIAL section of user manual (bug #25892).

Changes from 0.6.0 to 0.6.1:

  * Statistical bug fixes:

    - Report correct standardized regression coefficients in linear
      regression output (bug #23567).

  * Bug fixes that affect PSPP and PSPPIRE:

    - Avoid crash with pie charts (bug #24014).

    - Don't append % to count totals (bug #24003).

    - Don't crash on bad input (bug #24031).

    - Don't crash if "end data." is not left aligned (bug #24115).

    - Change default workspace value to 64 MB, to avoid unnecessary
      disk accesses on modern machines.

  * PSPPIRE bug fixes:

    - Add ".sav" or ".por" suffix to filename when saving with Save_As
      (bug #23137).

    - Make it possible to reopen the output window on Windows (bug
      #24033).

    - A POSIX regular expression library is now included and used
      automatically if the host does not have one or has one that is
      inadequate.

  * Build fixes and changes:

    - Work around bug in GSL that prevented build with recent GCC
      versions without manually adding -fgnu89-inline to CFLAGS.

    - Also warn about missing prerequisites as we encounter them (bug
      #24445).

    - Distribute necessary files to allow users working from the
      distributed tarball to configure with --enable-gui-tools.

    - Append $(EXEEXT_FOR_BUILD) to output file name when building
      q2c, fixing build problems on Windows.

    - GSL 1.8 or later is now required.

    - Build errors with --enable-relocatable were fixed.

  * The German translations were removed, since native German speakers
    found them too poor to be useful.

Changes from 0.4.0 to 0.6.0:

  * The PSPP license is now version 3 or later of the GNU General
    Public License.  Previously, it was version 2 or later.

  * PSPP now has a graphical interface, called PSPPIRE.  This
    interface allows you to enter data and variable definitions
    interactively.  Commands may be executed in syntax form, or by
    using the interactive dialog boxes available from the dropdown
    menus.

  * A few sample syntax files are now included in the `examples'
    directory.

  * Numerous major and minor bugs have been fixed.

  Build changes:

    * The INSTALL file now reflects the details of how to install
      PSPP.  It is a tailored version of the generic installation
      instructions, instead of a verbatim copy.

    * iconv, which is ordinarily installed as part of a Unix-like
      system, is now required.  If you don't have it already, you can
      install GNU libiconv (http://www.gnu.org/software/libiconv/).

    * libxml2 and zlib are new optional dependencies.  They are
      required to use PSPP's support for reading Gnumeric files.

  Statistical procedure changes:

    * REGRESSION is a new procedure for fitting linear models to data
      via least-squares estimation.

    * NPAR TESTS is a new procedure for non-parametric tests.  In this
      release, it supports binomial and chi-square tests.

    * RANK is a new procedure to rank variables.  It supports numerous
      forms of ranking.

    * FREQUENCIES can now output histograms and pie charts.  These
      features were present in earlier releases, but not documented.

  User interface changes:

    * In many situations where PSPP once terminated with a fatal
      error, PSPP now recovers and continues execution.

    * PSPP is now able to start up and run even if it cannot find its
      configuration files.

    * Journaling of interactive commands to a disk file is now
      implemented.  By default, journaling is enabled, to a file named
      `pspp.jnl' in the current directory.  SET JOURNAL may be used to
      control journaling.

    * The use of `+' between syntax file names on the command line to
      prevent the dictionary from being cleared between their
      executions is no longer supported.  All syntax files are now
      executed as if `+' had been specified.

    * The -d/--define and -u/--undef command line options are no
      longer supported.  Instead, use /usr/bin/env or shell primitives
      to define or clear environment variables before invoking PSPP.

    * If a syntax file named named `rc' is found in a configuration
      directory (such as $HOME/.pspp), it is executed before any
      syntax file specified on the command line.  The -r or
      --no-statrc command line option may be used to disable this
      behavior.

  Output changes:

    * Output configuration options have changed.  Please refer to the
      manual for a full description of the available options.

      In consequence, you will need to reinstall your "devices" file.
      "make install" will do this for you.

    * Most error messages are now written to PSPP output files by
      default.  SET ERROR can be used to disable this behavior.

    * When invoked interactively, PSPP now by default produces output
      on the terminal, piping it through the "more" program.
      Previously, by default output was written only to file
      pspp.list.  On most terminals, the page length used for output
      automatically adapts to the terminal size, even if the terminal
      is resized.

    * ASCII driver:

      - This driver now supports charts in output.  Charts are written
        as separate files that the main output file refers to.  By
        default, charts are written in PNG format to files named
        pspp-1.png, pspp-2.png, and so on.

      - Configurations are provided that use VT100 (and xterm)
        line-drawing characters in tables.  The option "-o list-vt100"
        requests use of this device for output to pspp.list.

    * PostScript driver:

      - The default paper size is now determined using the PAPERSIZE
        environment variable, or the LC_PAPER locale category on
        systems that support it.  If these are not set, the default is
        now A4, instead of US letter.  To make US letter the default,
        set PAPERSIZE to "letter" in your environment.

      - Font metrics are now read from AFM files, instead of
        Groff-format metrics files.  PostScript fonts can now be
        embedded in output.

        In consequence, you will need to install an AFM file for each
        font used in PostScript output.  "make install" will install
        AFM files for the standard PostScript fonts, including the
        ones that the PostScript driver uses by default.

      - Standard paper sizes no longer need to be specified through a
        configuration file.  The "papersize" configuration file is no
        longer needed, or supported.

      - The PostScript prologue is no longer obtained from the
        "ps-prologue" configuration file.  This configuration file is
        no longer needed, or supported.

    * HTML driver:

      - The HTML prologue is no longer obtained from the
        "html-prologue" configuration file.  This configuration file
        is no longer needed, or supported.

  Command language changes:

    * The following commands are new:

      - GET DATA, which currently supports reading Gnumeric files and
        text data files.  It will be extended later to read other
        types of foreign data.

      - CD, to change the current directory.

      - INSERT, to execute a syntax file.

      - DELETE VARIABLES, to remove variables from the active file
        dictionary.

      - ADD DOCUMENT, to add text to active file documents.

      - CLOSE FILE HANDLE (a PSPP extension; see below).

      - XEXPORT, a PSPP extension that is a transformation equivalent
        to EXPORT.

    * The following functions for transformation expressions are new:

      - DATEDIFF, for computing the difference of two dates.

      - DATESUM, for advancing a date by a specified duration.

      - VALUELABEL, to obtain the value label for a value.

    * PSPP now supports very long string variables (over 255 bytes
      long).

    * MATCH FILES now supports the FIRST and LAST subcommands.

    * Previous versions of PSPP prohibited using commands to both read and
      write a single file at the same time.  Now, PSPP allows this, and
      the new version of the file atomically replaces the old version.

    * The following commands are no longer available.  They will be
      re-implemented in a later release:

      - CLEAR TRANSFORMATIONS

      - MATRIX DATA

      - REPEATING DATA

    * The PROCESS IF command, which was deprecated, has been removed.
      You may replace any usage of it by SELECT IF following
      TEMPORARY, which has the same effect.

    * The output format for variables created by VECTOR may now be
      specified as part of the VECTOR syntax.

  "Scratch files", a new PSPP extension:

    A scratch file, like a system file, consists of a dictionary and
    any number of cases.  Small scratch files are stored in memory;
    one that grows too large is written to disk.  By default, any file
    handle whose name begins with # is assumed to refer to a scratch
    file.

    Scratch files can be used just about anywhere a system or portable
    file can be used.  Also, portable files are now allowed in most
    places that system files were allowed in previous PSPP version.

    A new CLOSE FILE HANDLE command allows the storage associated with
    scratch files to be freed.  It also allows file handles to be
    reassigned to new files.

    For more information on scratch files, refer to the "File Handles"
    section in the PSPP manual.  For specifics of what commands now
    allow what kinds of files to be specified, refer to the
    documentation on those particular commands.

  Data access changes:

    * Binary formats and IBM/360 formats, including ASCII/EBCDIC
      translation, are now supported.  Use FILE HANDLE to specify the
      format of these files.

    * Little-endian, big-endian, and VAX-endian formats are now
      supported for integer binary formats when reading and writing
      data files.  The new RIB and WIB subcommands on the SET command
      control endianness of integer data.  The default is the host's
      native endianness.

    * IEEE 754, VAX, and IBM hexadecimal formats are now supported for
      floating point binary formats when reading and writing data
      files.  The new RRB and WRB subcommands on the SET command
      control the floating point format.  The default is the host's
      native floating point format.

    * DATA LIST now supports the SKIP subcommand, to skip records at
      the beginning of a file.  For compatibility, DATA LIST now
      treats N format as F format for FREE and LIST format input.

    * The SAVE and XSAVE commands now support the UNSELECTED,
      PERMISSIONS, NAMES, and MAP subcommands.

    * The EXPORT command has been re-implemented to obtain better
      results.  Support for the UNSELECTED, DIGITS, and TYPE
      subcommands has been added.

    * For compatibility, PRINT now inserts a space at the beginning of
      every output line, even lines that would otherwise be blank,
      when OUTFILE is specified.  (The behavior of WRITE is
      unchanged.)

    * For compatibility, PRINT EJECT now inserts the digit `1' at the
      beginning of each line that should begin a new page.

    * For compatibility, WRITE now outputs the system-missing value as
      a field filled with spaces.  Binary formats are an exception.
      (The behavior of PRINT is unchanged.)

  Documentation:

    * Input and output format descriptions have been rewritten.  They
      now precisely describe what is accepted on input and written on
      output.

    * The descriptions of the PSPP system and portable file formats
      have been extensively revised and improved.

  For developers, the build system now requires Autoconf 2.60 and
  Automake 1.10.
\f
Changes from 0.3.0 to 0.4.0:

  Changes in build dependencies:

    * The GNU Scientific Library (libgsl), version 1.6 or later, is
      now required.

    * libplot from GNU plotutils is optional.  Without it, the new
      graphing features will not work.  If you do not have it
      installed, you must run `configure' with --without-libplot.

    * libgmp2 is no longer a dependency.

  Newly implemented commands and statistical features:

    * EXAMINE, including its graphing features.

    * FREQUENCIES now supports percentiles.

    * ONEWAY.

    * PERMISSIONS.

    * SHOW.

    * SORT CASES now sorts stably, that is, two cases with equal sort
      criteria will be in the same relative order before and after the
      sort.

    * T-TEST (re-written).

    * DATE and USE.  These commands are parsed but otherwise ignored,
      to enhance compatibility with certain command files that invoke
      them unnecessarily.

    * VARIABLE WIDTH, VARIABLE ALIGNMENT, and VARIABLE LEVEL.  These
      currently have no effect on PSPP output, but their values are
      written to and read from system files and thus may affect
      third-party software.

    * SET EPOCH implemented.

    * DATA LIST FREE and DATA LIST LIST now support arbitrary field
      delimiters.

    * FILE HANDLE now supports custom tab widths.

  Long variable names (and other identifiers) are now supported.  Up
  to the first 64 bytes of each identifier is significant.  PSPP now
  reads and writes system files compatible with SPSS version 12.

  New --algorithm and --syntax command line options allow
  SPSS-compatible or enhanced modes to be selected.

  Support for transformation expressions has been rewritten and
  significantly improved.  Refer to the manual for details.

  Calculation of moments (mean, standard deviation, kurtosis,
  skewness) has been rewritten and should now be more accurate.  In
  --algorithm=enhanced mode moments may be more accurate than SPSS in
  some cases.

  Numerous bugs have been fixed, too many to mention here.  Many new
  tests have been added, leading to the discovery and fixing of many
  of these bugs.

  The ASCII output driver can now squeeze multiple blank lines into
  single blank lines.

  Much of the code has been rewritten and refactored.  It is now much
  cleaner.

  The FILE TYPE and REPEATING DATA commands have been disabled for
  this release because their implementations were deemed too buggy to
  be useful.  They will be fixed and replaced in a future release.

  New pspp-mode for Emacs (in pspp-mode.el).

  Added rudimentary command-line completion for interactive input.

  lib/julcal and lib/dcdflib are no longer used, so they have been
  removed.

  For developers, the build system now requires Autoconf 2.58 and
  Automake 1.7.  The included gettext has been updated to version
  0.12.1.

  Some reports state that Texinfo 4.8, the latest version, may be
  necessary to successfully format the documentation on some systems.

Version 0.3.0 changes since 0.2.3:

  Bugs fixed:

    * Using alphanumeric variables in functions under AGGREGATE
      segfaulted.  Fixed.

    * Under certain circumstances, the final case would be omitted
      from the results of an AGGREGATE operation.  Fixed.

    * Undefined behavior was invoked by referencing a freed pointer
      under certain circumstances.  Fixed.

    * A wrong record size was displayed when paging the active file to
      disk.  Fixed.

    * Not having enough temporary space for sorting caused a core
      dump.  Fixed.

    * Syntax errors in function descriptions on AGGREGATE caused core
      dumps.  Fixed.

    * A null pointer was dereferenced, causing a core dump, when
      PERCENTILES was specified on FREQUENCIES.  This fixes the
      problem, but PSPP still doesn't calculate percentiles.

    * SORT always sorted in ascending order.  Fixed.

    * Some minor memory leaks in the expression parser were removed.

    * Many assertions fixed for strict ANSI C compliance.

  New features:

    * SET ECHO ON now implemented, but turned off by default.

    * PRINT specifier supported on END REPEAT.

  Other:

    * System libgmp2 library is used if installed instead of
      unconditionally using the included libgmp2 subset.

    * Extensive code cleanup, which continues.

    * Added CORRELATIONS command parser, but not implemented.

Version 0.2.3 changes since 0.2.2:

  Bugs fixed:

    * SPLIT FILE with a string variable caused a core dump.  Fixed.

    * Nested INCLUDEs didn't work.  Fixed.

    * The MATCH FILES procedure set the values of variables not present
      to 0.  It should have been SYSMIS.  This is now fixed.

    * The REMARK command was too aggressive about skipping lines.  It
      didn't like being the last command in a file.

    * Comment parsing wasn't consistent with the rest of the code in its
      idea of where one command ends and another starts.  This meant
      that sometimes commands would be mysteriously ignored.  Thanks to
      Dr. Dirk Melcher <BZN-mdksh@t-online.de> for reporting this bug.

    * The TABLE subcommand on MATCH FILES worked only erratically at
      best.  This fixes it.  Thanks to Dr. Dirk Melcher
      <BZN-mdksh@t-online.de> for reporting this bug.

    * VARIABLE LABELS rejected a slash before the first variable
      specification, contradicting the documentation.  Thanks to Walter
      M. Gray <graywm@northernc.on.ca> for reporting this bug.

    * Because of an incorrect optimization in memory allocation,
      CROSSTABS sometimes segfaulted when asked to output multiple
      tables.  Thanks to Walter M. Gray <graywm@northernc.on.ca> for
      reporting this bug.

    * CROSSTABS didn't display value labels for column and row
      variables.  Thanks to Walter M. Gray <graywm@northernc.on.ca> for
      reporting this bug.

    * WRITE didn't write line ends.  Fixed.  Thanks to Dr. Dirk Melcher
      <BZN-mdksh@t-online.de> for reporting this bug.

    * The TABLE subcommand on MATCH FILES worked only erratically at
      best.  This fixes it.  Thanks to Dr. Dirk Melcher
      <BZN-mdksh@t-online.de> for reporting this bug.

    * VARIABLE LABELS rejected a slash before the first variable
      specification, contradicting the documentation.  Thanks to Walter
      M. Gray <graywm@northernc.on.ca> for reporting this bug.

    * Because of an incorrect optimization in memory allocation,
      CROSSTABS sometimes segfaulted when asked to output multiple
      tables.  Thanks to Walter M. Gray <graywm@northernc.on.ca> for
      reporting this bug.

    * CROSSTABS didn't display value labels for column and row
      variables.  Thanks to Walter M. Gray <graywm@northernc.on.ca> for
      reporting this bug.

    * WRITE didn't write line ends.  Fixed.  Thanks to Dr. Dirk Melcher
      <BZN-mdksh@t-online.de> for reporting this bug.

    * MATCH FILES corrupted memory and dumped core on some syntax
      errors.  Fixed.

    * MATCH FILES should set numeric values not available to the
      system-missing value, not to 0.  Thanks to Dr. Dirk Melcher
      <BZN-mdksh@t-online.de> for reporting this bug.

    * KEEP didn't work properly on the SAVE procedure.  Fixed.  Thanks
      to Ralf Geschke <ralf@kuerbis.org> for reporting this bug.

    * Memory leak fix.

    * Some systems didn't like the way open_file was coded.  Thanks to
      Hankin <hankin@rogue.consultco.com> for pointing this out.

    * The SAVE procedure didn't save long string variables properly.
      Fixed by this patch.  Thanks to Hankin
      <hankin@rogue.consultco.com> for this patch.

    * Minor documentation fixes for MATCH FILES.

Version 0.2.2 changes since 0.2.1:

  Bugs fixed:

    * Fix behavior of PRINT SPACE for negative arguments.

    * Fix reading some unusual system files.

    * Fix LIST problems with very long variables.  Thanks to Hankin
      <hankin@dunno.com> for this bug report.

    * Fix problems with some string format specifiers.

    * Fix use of $CASENUM in expressions.  Thanks to Dirk Melcher
      <BZN-mdksh@t-online.de> for reporting this bug.

    * Additional DATA LIST FREE and DATA LIST LIST fixes.  Thanks to
      Hankin <hankin@dunno.com> again on this one.

    * Sometimes you may encounter a PSPP script that has to be
      interpreted in interactive mode.  Now you can use the -i flag to
      do this.

    * Warnings for egcs 1.1.1 cleaned up.  (However you'll get lots of
      `unused variable' warnings under gcc 2.7.2.3, fixing this will
      take more effort.)

    * Tests fixed.

    * The files in gmp need the internationalization directory in
      their include path.  Thanks to OKUJI Yoshinori
      <okuji@kuicr.kyoto-u.ac.jp> for pointing this out.

Version 0.2.1 changes since 0.2.0:

  Bugs fixed:

    * Remember to include examples/ directory in distribution :-)

    * Fixed gmp compile problems for some non-i386 architectures.
      Thanks to Hans Olav Eggestad <olav@jordforsk.nlh.no> and others
      for reporting this.

    * DATA LIST FREE and DATA LIST LIST parsing of input files is now
      matches the documented behavior exactly, and error messages are
      more helpful.  Thanks to Mark H. Wood <mwood@IUPUI.Edu>.

Version 0.2.0 changes since 0.1.0:

  Procedures now implemented:
    * CROSSTABS.  Please see documentation for caveats.

  Transformations and utilities now implemented:
    * AGGREGATE
    * APPLY DICTIONARY
    * CLEAR TRANSFORMATIONS
    * DISPLAY (all subcommands).
    * ERASE
    * FLIP
    * EXPORT
    * HOST
    * IMPORT
    * MATCH FILES
    * MATRIX DATA
    * NEW FILE
    * REPEATING DATA

  Support for input and output through pipes: "|command" and
  "command|" filenames; support for special filenames "-", "stdin",
  "stdout", "stderr".

  New command-line features:
    * New option --testing-mode: Invoke heuristics to assist testing.
    * New option --safer, -s: Don't allow certain unsafe operations.
    * New option --command=CMD, -c CMD: Perform literal command CMD.
    * rc file ~/.pspp/rc is executed before any other files.
    * Now multiple syntax files can be specified.

  Operator LAG is now implemented.

  Added missing FILE subcommand to REREAD.

  Table output manager completely rewritten.

  Device configuration file syntax changed.  You will need to
  reinstall your `devices' file.

  New output driver for HTML.

  PostScript driver and prologue simplified.

  Many bugs fixed.  General source-code cleanup.

  Added Texinfo documentation for:
    * PSPP system file format
    * PSPP portable file format
    * How to write input for q2c parser generator
    * HTML driver

  PSPP language is now fully documented.  Please report any
  inaccuracies or omissions in the documentation.

Changes for version 0.1.0:

  First public release.  For changes from unreleased development
  versions, please see ONEWS.
\f
----------------------------------------------------------------------
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   the copyright notice and this permission notice are preserved, thus
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\f
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