Section: User Contributed Perl Documentation (3)
Updated: 2021-01-27
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Text::BibTeX::Bib - defines the "Bib" database structure  


   $bibfile = Text::BibTeX::File $filename->new;
   $bibfile->set_structure ('Bib',
                            # Default option values:
                            sortby => 'name',
                            namestyle => 'full'
                            nameorder => 'first',
                            atitle => 1,
                            labels => 'numeric');

   # Alternate option values:
   $bibfile->set_option (sortby => 'year');
   $bibfile->set_option (namestyle => 'nopunct');
   $bibfile->set_option (namestyle => 'nospace');
   $bibfile->set_option (nameorder => 'last');
   $bibfile->set_option (atitle => 0);   
   $bibfile->set_option (labels => 'alpha');   # not implemented yet!

   # parse entry from $bibfile and automatically make it a BibEntry
   $entry = Text::BibTeX::Entry->new($bibfile);

   # or get an entry from somewhere else which is hard-coded to be
   # a BibEntry
   $entry = Text::BibTeX::BibEntry->new(...);

   $sortkey = $entry->sort_key;
   @blocks = $entry->format;



(NOTE! Do not believe everything you read in this document. The classes described here are unfinished and only lightly tested. The current implementation is a proof-of-principle, to convince myself (and anyone who might be interested) that it really is possible to reimplement BibTeX 0.99 in Perl using the core "Text::BibTeX" classes; this principle is vaguely demonstrated by the current "Bib*" modules, but not really proved. Many important features needed to reimplement the standard styles of BibTeX 0.99 are missing, even though this document may brashly assert otherwise. If you are interested in using these classes, you should start by reading and grokking the code, and contributing the missing bits and pieces that you need.)

"Text::BibTeX::Bib" implements the database structure for bibliographies as defined by the standard styles of BibTeX 0.99. It does this by providing two classes, "BibStructure" and "BibEntry" (the leading "Text::BibTeX" is implied, and will be omitted for the rest of this document). These two classes, being specific to bibliographic data, are outside of the core "Text::BibTeX" class hierarchy, but are distributed along with it as they provide a canonical example of a specific database structure using classes derived from the core hierarchy.

"BibStructure", which derives from the "Structure" class, deals with the structure as a whole: it handles structure options and describes all the types and fields that make up the database structure. If you're interested in writing your own database structure modules, the standard interface for both of these is described in Text::BibTeX::Structure; if you're just interested in finding out the exact database structure or the options supported by the "Bib" structure, you've come to the right place. (However, you may have to wade through a bit of excess verbiage due to this module's dual purpose: first, to reimplement the standard styles of BibTeX 0.99, and second, to provide an example for other programmers wishing to implement new or derived database structure modules.)

"BibEntry" derives from the "StructuredEntry" class and provides methods that operate on individual entries presumed to come from a database conforming to the structure defined by the "BibStructure" class. (Actually, to be completely accurate, "BibEntry" inherits from two intermediate classes, "BibSort" and "BibFormat". These two classes just exist to reduce the amount of code in the "Bib" module, and thanks to the magic of inheritance, their existence is usually irrelevant. But you might want to consult those two classes if you're interested in the gory details of sorting and formatting entries from BibTeX 0.99-style bibliography databases.)  


"BibStructure" handles several user-supplied ``structure options'' and methods for dealing with them. The options currently supported by the "Bib" database structure, and the values allowed for them, are:
How to sort entries. Valid values: "name" (sort on author names, year, and title), "year" (sort on year, author names, and title). Sorting on ``author names'' is a bit more complicated than just using the "author" field; see Text::BibTeX::BibSort for details. Default value: "name".
How to print author (and editor) names: "full" for unabbreviated first names, "abbrev" for first names abbreviated with periods, "nopunct" for first names abbreviated with space but no periods, and "nospace" to abbreviate without space or periods. Default value: "full".
The order in which to print names: "first" for ``first von last jr'' order, and "last" for ``von last jr first'' order. Default value: "first".
A boolean option: if true, non-book titles will be changed to ``sentence capitalization:'' words following colons and sentence-ending punctuation will be capitalized, and everything else at brace-depth zero will be changed to lowercase. Default value: true.
The type of bibliographic labels to generate: "numeric" or "alpha". (Alphabetic labels are not yet implemented, so this option is currently ignored.) Default value: "numeric".

Also, several ``markup options'' are supported. Markup options are distinct because they don't change how text is extracted from the database entries and subsequently mangled; rather, they supply bits of markup that go around the database-derived text. Markup options are always two-element lists: the first to ``turn on'' some feature of the markup language, and the second to turn it off. For example, if your target language is LaTeX2e and you want journal names emphasized, you would supply a list reference "['\emph{','}']" for the "journal_mkup" option. If you were instead generating HTML, you might supply "['<emph>','</emph>']". To keep the structure module general with respect to markup languages, all markup options are empty by default. (Or, rather, they are all references to lists consisting of two empty strings.)

Markup to add around the list of author names.
Markup to add around non-book (article) titles.
Markup to add around book titles.
Markup to add around journal names.

Option methods

As required by the "Text::BibTeX::Structure" module, "Text::BibTeX::Bib" provides two methods for handling options: "known_option" and "default_option". (The other two option methods, "set_options" and "get_options", are just inherited from "Text::BibTeX::Structure".)
known_option (OPTION)
Returns true if OPTION is one of the options on the above list.
default_option (OPTION)
Returns the default value of OPTION, or "croak"s if OPTION is not a supported option.


The other purpose of a structure class is to provide a method, "describe_entry", that lists the allowed entry types and the known fields for the structure. Programmers wishing to write their own database structure module should consult Text::BibTeX::Structure for the conventions and requirements of this method; the purpose of the present document is to describe the "Bib" database structure.

The allowed entry types, and the fields recognized for them, are:

Required fields: "author", "title", "journal", "year". Optional fields: "volume", "number", "pages", "month", "note".
Required fields: "title", "publisher", "year". Optional fields: "series", "address", "edition", "month", "note". Constrained fields: exactly one of "author", "editor"; at most one of "volume", "number".
Required fields: "title". Optional fields: "author", "howpublished", "address", "month", "year", "note".
Required fields: "publisher", "year". Optional fields: "series", "type", "address", "edition", "month", "note". Constrained fields: exactly one of "author", "editor"; at least one of "chapter", "pages"; at most one of "volume", "number".
Required fields: "author", "title", "booktitle", "publisher", "year". Optional fields: "editor", "series", "type", "chapter", "pages", "address", "edition", "month", "note". Constrained fields: at most one of "volume", "number".
Required fields: "author", "title", "booktitle", "year". Optional fields: "editor", "series", "pages", "address", "month", "organization", "publisher", "note". Constrained fields: at most one of "volume", "number".
Required fields: "title". Optional fields: "author", "organization", "address", "edition", "month", "year", "note".
Required fields: "author", "title", "school", "year". Optional fields: "type", "address", "month", "note".
Required fields: none. Optional fields: "author", "title", "howpublished", "month", "year", "note".
Required fields: "author", "title", "school", "year". Optional fields: "type", "address", "month", "note".
Required fields: "title", "year". Optional fields: "editor", "series", "address", "month", "organization", "publisher", "note". Constrained fields: at most one of "volume", "number".
Required fields: "author", "title", "institution", "year". Optional fields: "type", "number", "address", "month", "note".
Required fields: "author", "title", "note". Optional fields: "month", "year".


The second class provided by the "Text::BibTeX::Bib" module is "BibEntry" (again, a leading "Text::BibTeX" is implied). This being a structured entry class, it derives from "StructuredEntry". The conventions and requirements for such a class are documented in Text::BibTeX::Structure for the benefit of programmers implementing their own structure modules.

If you wish to write utilities making use of the "Bib" database structure, then you should call one of the ``officially supported'' methods provided by the "BibEntry" class. Currently, there are only two of these: "sort_key" and "format". These are actually implemented in the "BibSort" and "BibFormat" classes, respectively, which are base classes of "BibEntry". Thus, see Text::BibTeX::BibSort and Text::BibTeX::BibFormat for details on these two methods.  


Text::BibTeX::Structure, Text::BibTeX::BibSort, Text::BibTeX::BibFormat.  


Greg Ward <gward@python.net>  


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.



Option methods