Provided by: libtext-bibtex-perl_0.71-1build1_amd64 bug


       Text::BibTeX - interface to read and parse BibTeX files


          use Text::BibTeX;

          $bibfile = new Text::BibTeX::File "foo.bib";
          $newfile = new Text::BibTeX::File ">newfoo.bib";

          while ($entry = new Text::BibTeX::Entry $bibfile)
             next unless $entry->parse_ok;

                .             # hack on $entry contents, using various
                .             # Text::BibTeX::Entry methods

             $entry->write ($newfile);


       The "Text::BibTeX" module serves mainly as a high-level introduction to the "Text::BibTeX"
       library, for both code and documentation purposes.  The code loads the two fundamental
       modules for processing BibTeX files ("Text::BibTeX::File" and "Text::BibTeX::Entry"), and
       this documentation gives a broad overview of the whole library that isn't available in the
       documentation for the individual modules that comprise it.

       In addition, the "Text::BibTeX" module provides a number of miscellaneous functions that
       are useful in processing BibTeX data (especially the kind that comes from bibliographies
       as defined by BibTeX 0.99, rather than generic database files).  These functions don't
       generally fit in the object-oriented class hierarchy centred around the
       "Text::BibTeX::Entry" class, mainly because they are specific to bibliographic data and
       operate on generic strings (rather than being tied to a particular BibTeX entry).  These
       are also documented here, in "MISCELLANEOUS FUNCTIONS".

       Note that every module described here begins with the "Text::BibTeX" prefix.  For brevity,
       I have dropped this prefix from most class and module names in the rest of this manual
       page (and in most of the other manual pages in the library).


       The "Text::BibTeX" library includes a number of modules, many of which provide classes.
       Usually, the relationship is simple and obvious: a module provides a class of the same
       name---for instance, the "Text::BibTeX::Entry" module provides the "Text::BibTeX::Entry"
       class.  There are a few exceptions, though: most obviously, the "Text::BibTeX" module
       doesn't provide any classes itself, it merely loads two modules ("Text::BibTeX::Entry" and
       "Text::BibTeX::File") that do.  The other exceptions are mentioned in the descriptions
       below, and discussed in detail in the documentation for the respective modules.

       The modules are presented roughly in order of increasing specialization: the first three
       are essential for any program that processes BibTeX data files, regardless of what kind of
       data they hold.  The later modules are specialized for use with bibliographic databases,
       and serve both to emulate BibTeX 0.99's standard styles and to provide an example of how
       to define a database structure through such specialized modules.  Each module is fully
       documented in its respective manual page.

           Loads the two fundamental modules ("Entry" and "File"), and provides a number of
           miscellaneous functions that don't fit anywhere in the class hierarchy.

           Provides an object-oriented interface to BibTeX database files.  In addition to the
           obvious attributes of filename and filehandle, the "file" abstraction manages
           properties such as the database structure and options for it.

           Provides an object-oriented interface to BibTeX entries, which can be parsed from
           "File" objects, arbitrary filehandles, or strings.  Manages all the properties of a
           single entry: type, key, fields, and values.  Also serves as the base class for the
           structured entry classes (described in detail in Text::BibTeX::Structure).

           Provides an object-oriented interface to values and simple values, high-level
           constructs that can be used to represent the strings associated with each field in an
           entry.  Normally, field values are returned simply as Perl strings, with macros
           expanded and multiple strings "pasted" together.  If desired, you can instruct
           "Text::BibTeX" to return "Text::BibTeX::Value" objects, which give you access to the
           original form of the data.

           Provides the "Structure" and "StructuredEntry" classes, which serve primarily as base
           classes for the two kinds of classes that define database structures.  Read this man
           page for a comprehensive description of the mechanism for implementing Perl classes
           analogous to BibTeX "style files".

           Provides the "BibStructure" and "BibEntry" classes, which serve two purposes: they
           fulfill the same role as the standard style files of BibTeX 0.99, and they give an
           example of how to write new database structures.  These ultimately derive from,
           respectively, the "Structure" and "StructuredEntry" classes provided by the
           "Structure" module.

           One of the "BibEntry" class's base classes: handles the generation of sort keys for
           sorting prior to output formatting.

           One of the "BibEntry" class's base classes: handles the formatting of bibliographic
           data for output in a markup language such as LaTeX.

           A class used by the "Bib" structure and specific to bibliographic data as defined by
           BibTeX itself: parses individual author names into "first", "von", "last", and "jr"

           Also specific to bibliographic data: puts split-up names (as parsed by the "Name"
           class) back together in a custom way.

       For a first time through the library, you'll probably want to confine your reading to
       Text::BibTeX::File and Text::BibTeX::Entry.  The other modules will come in handy
       eventually, especially if you need to emulate BibTeX in a fairly fine grained way (e.g.
       parsing names, generating sort keys).  But for the simple database hacks that are the
       bread and butter of the "Text::BibTeX" library, the "File" and "Entry" classes are the
       bulk of what you'll need.  You may also find some of the material in this manual page
       useful, namely "CONSTANT VALUES" and "UTILITY FUNCTIONS".


       The "Text::BibTeX" module has a number of optional exports, most of them constant values
       described in "CONSTANT VALUES" below.  The default exports are a subset of these constant
       values that are used particularly often, the "entry metatypes" (also accessible via the
       export tag "metatypes").  Thus, the following two lines are equivalent:

          use Text::BibTeX;
          use Text::BibTeX qw(:metatypes);

       Some of the various subroutines provided by the module are also exportable.  "bibloop",
       "split_list", "purify_string", and "change_case" are all useful in everyday processing of
       BibTeX data, but don't really fit anywhere in the class hierarchy.  They may be imported
       from "Text::BibTeX" using the "subs" export tag.  "check_class" and "display_list" are
       also exportable, but only by name; they are not included in any export tag.  (These two
       mainly exist for use by other modules in the library.)  For instance, to use
       "Text::BibTeX" and import the entry metatype constants and the common subroutines:

          use Text::BibTeX qw(:metatypes :subs);

       Another group of subroutines exists for direct manipulation of the macro table maintained
       by the underlying C library.  These functions (see "Macro table functions", below) allow
       you to define, delete, and query the value of BibTeX macros (or "abbreviations").  They
       may be imported en masse using the "macrosubs" export tag:

          use Text::BibTeX qw(:macrosubs);


       The "Text::BibTeX" module makes a number of constant values available.  These correspond
       to the values of various enumerated types in the underlying C library, btparse, and their
       meanings are more fully explained in the btparse documentation.

       Each group of constants is optionally exportable using an export tag given in the
       descriptions below.

       Entry metatypes
           "metatype" method in the "Entry" class always returns one of these values.  The latter
           three describe, respectively, "comment", "preamble", and "string" entries;
           "BTE_REGULAR" describes all other entry types.  "BTE_UNKNOWN" should never be seen
           (it's mainly useful for C code that might have to detect half-baked data structures).
           See also btparse.  Export tag: "metatypes".

       AST node types
           "BTAST_STRING", "BTAST_MACRO", "BTAST_NUMBER".  Used to distinguish the three kinds of
           simple values---strings, macros, and numbers.  The "SimpleValue" class' "type" method
           always returns one of these three values.  See also Text::BibTeX::Value, btparse.
           Export tag: "nodetypes".

       Name parts
           "BTN_FIRST", "BTN_VON", "BTN_LAST", "BTN_JR", "BTN_NONE".  Used to specify the various
           parts of a name after it has been split up.  These are mainly useful when using the
           "NameFormat" class.  See also bt_split_names and bt_format_names.  Export tag:

       Join methods
           "BTJ_MAYTIE", "BTJ_SPACE", "BTJ_FORCETIE", "BTJ_NOTHING".  Used to tell the
           "NameFormat" class how to join adjacent tokens together; see Text::BibTeX::NameFormat
           and bt_format_names.  Export tag: "joinmethods".


       "Text::BibTeX" provides several functions that operate outside of the normal class
       hierarchy.  Of these, only "bibloop" is likely to be of much use to you in writing
       everyday BibTeX-hacking programs; the other two ("check_class" and "display_list") are
       mainly provided for the use of other modules in the library.  They are documented here
       mainly for completeness, but also because they might conceivably be useful in other

       bibloop (ACTION, FILES [, DEST])
           Loops over all entries in a set of BibTeX files, performing some caller-supplied
           action on each entry.  FILES should be a reference to the list of filenames to
           process, and ACTION a reference to a subroutine that will be called on each entry.
           DEST, if given, should be a "Text::BibTeX::File" object (opened for output) to which
           entries might be printed.

           The subroutine referenced by ACTION is called with exactly one argument: the
           "Text::BibTeX::Entry" object representing the entry currently being processed.
           Information about both the entry itself and the file where it originated is available
           through this object; see Text::BibTeX::Entry.  The ACTION subroutine is only called if
           the entry was successfully parsed; any syntax errors will result in a warning message
           being printed, and that entry being skipped.  Note that all successfully parsed
           entries are passed to the ACTION subroutine, even "preamble", "string", and "comment"
           entries.  To skip these pseudo-entries and only process "regular" entries, then your
           action subroutine should look something like this:

              sub action {
                 my $entry = shift;
                 return unless $entry->metatype == BTE_REGULAR;
                 # process $entry ...

           If your action subroutine needs any more arguments, you can just create a closure
           (anonymous subroutine) as a wrapper, and pass it to "bibloop":

              sub action {
                 my ($entry, $extra_stuff) = @_;
                 # ...

              my $extra = ...;
              Text::BibTeX::bibloop (sub { &action ($_[0], $extra) }, \@files);

           If the ACTION subroutine returns a true value and DEST was given, then the processed
           entry will be written to DEST.

           Ensures that a PACKAGE implements a class meeting certain requirements.  First, it
           inspects Perl's symbol tables to ensure that a package named PACKAGE actually exists.
           Then, it ensures that the class named by PACKAGE derives from SUPERCLASS (using the
           universal method "isa").  This derivation might be through multiple inheritance, or
           through several generations of a class hierarchy; the only requirement is that
           SUPERCLASS is somewhere in PACKAGE's tree of base classes.  Finally, it checks that
           PACKAGE provides each method listed in METHODS (a reference to a list of method
           names).  This is done with the universal method "can", so the methods might actually
           come from one of PACKAGE's base classes.

           DESCRIPTION should be a brief string describing the class that was expected to be
           provided by PACKAGE.  It is used for generating warning messages if any of the class
           requirements are not met.

           This is mainly used by the supervisory code in "Text::BibTeX::Structure", to ensure
           that user-supplied structure modules meet the rules required of them.

       display_list (LIST, QUOTE)
           Converts a list of strings to the grammatical conventions of a human language
           (currently, only English rules are supported).  LIST must be a reference to a list of
           strings.  If this list is empty, the empty string is returned.  If it has one element,
           then just that element is returned.  If it has two elements, then they are joined with
           the string " and " and the resulting string is returned.  Otherwise, the list has N
           elements for N >= 3; elements 1..N-1 are joined with commas, and the final element is
           tacked on with an intervening ", and ".

           If QUOTE is true, then each string is encased in single quotes before anything else is

           This is used elsewhere in the library for two very distinct purposes: for generating
           warning messages describing lists of fields that should be present or are conflicting
           in an entry, and for generating lists of author names in formatted bibliographies.


       In addition to loading the "File" and "Entry" modules, "Text::BibTeX" loads the XSUB code
       which bridges the Perl modules to the underlying C library, btparse.  This XSUB code
       provides a number of miscellaneous utility functions, most of which are put into other
       packages in the "Text::BibTeX" family for use by the corresponding classes.  (For
       instance, the XSUB code loaded by "Text::BibTeX" provides a function
       "Text::BibTeX::Entry::parse", which is actually documented as the "parse" method of the
       "Text::BibTeX::Entry" class---see Text::BibTeX::Entry.  However, for completeness this
       function---and all the other functions that become available when you "use
       Text::BibTeX"---are at least mentioned here.  The only functions from this group that
       you're ever likely to use are described in "Generic string-processing functions".

   Startup/shutdown functions
       These just initialize and shutdown the underlying C library.  Don't call either one of
       them; the "Text::BibTeX" startup/shutdown code takes care of it as appropriate.  They're
       just mentioned here for completeness.

       initialize ()
       cleanup ()

   Generic string-processing functions
       split_list (STRING, DELIM [, FILENAME [, LINE [, DESCRIPTION]]])
           Splits a string on a fixed delimiter according to the BibTeX rules for splitting up
           lists of names.  With BibTeX, the delimiter is hard-coded as "and"; here, you can
           supply any string.  Instances of DELIM in STRING are considered delimiters if they are
           at brace-depth zero, surrounded by whitespace, and not at the beginning or end of
           STRING; the comparison is case-insensitive.  See bt_split_names for full details of
           how splitting is done (it's not the same as Perl's "split" function).

           Returns the list of strings resulting from splitting STRING on DELIM.

       purify_string (STRING [, OPTIONS])
           "Purifies" STRING in the BibTeX way (usually for generation of sort keys).  See
           bt_misc for details; note that, unlike the C interface, "purify_string" does not
           modify STRING in-place.  A purified copy of the input string is returned.

           OPTIONS is currently unused.

       change_case (TRANFORM, STRING [, OPTIONS])
           Transforms the case of STRING according to TRANSFORM (a single character, one of 'u',
           'l', or 't').  See bt_misc for details; again, "change_case" differs from the C
           interface in that STRING is not modified in-place---the input string is copied, and
           the transformed copy is returned.

   Entry-parsing functions
       Although these functions are provided by the "Text::BibTeX" module, they are actually in
       the "Text::BibTeX::Entry" package.  That's because they are implemented in C, and thus
       loaded with the XSUB code that "Text::BibTeX" loads; however, they are actually methods in
       the "Text::BibTeX::Entry" class.  Thus, they are documented as methods in

       parse_s (ENTRY_STRUCT, TEXT)

   Macro table functions
       These functions allow direct access to the macro table maintained by btparse, the C
       library underlying "Text::BibTeX".  In the normal course of events, macro definitions
       always accumulate, and are only defined as a result of parsing a macro definition
       (@string) entry.  btparse never deletes old macro definitions for you, and doesn't have
       any built-in default macros.  If, for example, you wish to start fresh with new macros for
       every file, use "delete_all_macros".  If you wish to pre-define certain macros, use
       "add_macro_text".  (But note that the "Bib" structure, as part of its mission to emulate
       BibTeX 0.99, defines the standard "month name" macros for you.)

       See also bt_macros in the btparse documentation for a description of the C interface to
       these functions.

       add_macro_text (MACRO, TEXT [, FILENAME [, LINE]])
           Defines a new macro, or redefines an old one.  MACRO is the name of the macro, and
           TEXT is the text it should expand to.  FILENAME and LINE are just used to generate any
           warnings about the macro definition.  The only such warning occurs when you redefine
           an old macro: its value is overridden, and "add_macro_text()" issues a warning saying

       delete_macro (MACRO)
           Deletes a macro from the macro table.  If MACRO isn't defined, takes no action.

       delete_all_macros ()
           Deletes all macros from the macro table.

       macro_length (MACRO)
           Returns the length of a macro's expansion text.  If the macro is undefined, returns 0;
           no warning is issued.

       macro_text (MACRO [, FILENAME [, LINE]])
           Returns the expansion text of a macro.  If the macro is not defined, issues a warning
           and returns "undef".  FILENAME and LINE, if supplied, are used for generating this
           warning; they should be supplied if you're looking up the macro as a result of finding
           it in a file.

   Name-parsing functions
       These are both private functions for the use of the "Name" class, and therefore are put in
       the "Text::BibTeX::Name" package.  You should use the interface provided by that class for
       parsing names in the BibTeX style.

       free (NAME_STRUCT)

   Name-formatting functions
       These are private functions for the use of the "NameFormat" class, and therefore are put
       in the "Text::BibTeX::NameFormat" package.  You should use the interface provided by that
       class for formatting names in the BibTeX style.

       create ([PARTS [, ABBREV_FIRST]])
       free (FORMAT_STRUCT)
       format_name (NAME_STRUCT, FORMAT_STRUCT)


       "Text::BibTeX" inherits several limitations from its base C library, btparse; see "BUGS
       AND LIMITATIONS" in btparse for details.  In addition, "Text::BibTeX" will not work with a
       Perl binary built using the "sfio" library.  This is because Perl's I/O abstraction layer
       does not extend to third-party C libraries that use stdio, and btparse most certainly does
       use stdio.


       btool_faq, Text::BibTeX::File, Text::BibTeX::Entry, Text::BibTeX::Value


       Greg Ward <>


       Copyright (c) 1997-2000 by Gregory P. Ward.  All rights reserved.  This file is part of
       the Text::BibTeX library.  This library is free software; you may redistribute it and/or
       modify it under the same terms as Perl itself.