Lingua::Stem::En--3pm

Lingua::Stem::En(3pm) User Contributed Perl DocumentationLingua::Stem::En(3pm)



NAME
       Lingua::Stem::En - Porter's stemming algorithm for 'generic' English

SYNOPSIS
           use Lingua::Stem::En;
           my $stems   = Lingua::Stem::En::stem({ -words => $word_list_reference,
                                               -locale => 'en',
                                           -exceptions => $exceptions_hash,
                                            });

DESCRIPTION
       This routine applies the Porter Stemming Algorithm to its parameters,
       returning the stemmed words.

       It is derived from the C program "stemmer.c" as found in freewais and
       elsewhere, which contains these notes:

          Purpose:    Implementation of the Porter stemming algorithm documented
                      in: Porter, M.F., "An Algorithm For Suffix Stripping,"
                      Program 14 (3), July 1980, pp. 130-137.
          Provenance: Written by B. Frakes and C. Cox, 1986.

       I have re-interpreted areas that use Frakes and Cox's "WordSize" func-
       tion. My version may misbehave on short words starting with "y", but I
       can't think of any examples.

       The step numbers correspond to Frakes and Cox, and are probably in
       Porter's article (which I've not seen).  Porter's algorithm still has
       rough spots (e.g current/currency, -ings words), which I've not
       attempted to cure, although I have added support for the British -ise
       suffix.

CHANGES
        1999.06.15 - Changed to '.pm' module, moved into Lingua::Stem namespace,
                     optionalized the export of the 'stem' routine
                     into the caller's namespace, added named parameters

        1999.06.24 - Switch core implementation of the Porter stemmer to
                     the one written by Jim Richardson <jimr AT maths.au>

        2000.08.25 - 2.11 Added stemming cache

        2000.09.14 - 2.12 Fixed *major* :( implementation error of Porter's algorithm
                     Error was entirely my fault - I completely forgot to include
                     rule sets 2,3, and 4 starting with Lingua::Stem 0.30.
                     -- Benjamin Franz

        2003.09.28 - 2.13 Corrected documentation error pointed out by Simon Cozens.

METHODS
       stem({ -words => \@words, -locale => 'en', -exceptions => \%exceptions
       });
           Stems a list of passed words using the rules of US English. Returns
           an anonymous array reference to the stemmed words.

           Example:

             my $stemmed_words = Lingua::Stem::En::stem({ -words => \@words,
                                                         -locale => 'en',
                                                     -exceptions => \%exceptions,
                                     });

       stem_caching({ -level => 0|1|2 });
           Sets the level of stem caching.

           '0' means 'no caching'. This is the default level.

           '1' means 'cache per run'. This caches stemming results during a
           single
               call to 'stem'.

           '2' means 'cache indefinitely'. This caches stemming results until
               either the process exits or the 'clear_stem_cache' method is
           called.

       clear_stem_cache;
           Clears the cache of stemmed words

NOTES
       This code is almost entirely derived from the Porter 2.1 module written
       by Jim Richardson.

SEE ALSO
        Lingua::Stem

AUTHOR
         Jim Richardson, University of Sydney
         jimr AT maths.au or http://www.maths.usyd.edu.au:8000/jimr.html

         Integration in Lingua::Stem by
         Benjamin Franz, FreeRun Technologies,
         snowhare AT nihongo.org or http://www.nihongo.org/snowhare/

COPYRIGHT
       Jim Richardson, University of Sydney Benjamin Franz, FreeRun Technolo-
       gies

       This code is freely available under the same terms as Perl.

BUGS
TODO
perl v5.8.7                       2004-07-25             Lingua::Stem::En(3pm)