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Diffstat (limited to 'contrib/perl5/lib/Text/Soundex.pm')
| -rw-r--r-- | contrib/perl5/lib/Text/Soundex.pm | 150 |
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diff --git a/contrib/perl5/lib/Text/Soundex.pm b/contrib/perl5/lib/Text/Soundex.pm deleted file mode 100644 index d588764..0000000 --- a/contrib/perl5/lib/Text/Soundex.pm +++ /dev/null @@ -1,150 +0,0 @@ -package Text::Soundex; -require 5.000; -require Exporter; - -@ISA = qw(Exporter); -@EXPORT = qw(&soundex $soundex_nocode); - -$VERSION = '1.0'; - -# $Id: soundex.pl,v 1.2 1994/03/24 00:30:27 mike Exp $ -# -# Implementation of soundex algorithm as described by Knuth in volume -# 3 of The Art of Computer Programming, with ideas stolen from Ian -# Phillips <ian@pipex.net>. -# -# Mike Stok <Mike.Stok@meiko.concord.ma.us>, 2 March 1994. -# -# Knuth's test cases are: -# -# Euler, Ellery -> E460 -# Gauss, Ghosh -> G200 -# Hilbert, Heilbronn -> H416 -# Knuth, Kant -> K530 -# Lloyd, Ladd -> L300 -# Lukasiewicz, Lissajous -> L222 -# -# $Log: soundex.pl,v $ -# Revision 1.2 1994/03/24 00:30:27 mike -# Subtle bug (any excuse :-) spotted by Rich Pinder <rpinder@hsc.usc.edu> -# in the way I handles leasing characters which were different but had -# the same soundex code. This showed up comparing it with Oracle's -# soundex output. -# -# Revision 1.1 1994/03/02 13:01:30 mike -# Initial revision -# -# -############################################################################## - -# $soundex_nocode is used to indicate a string doesn't have a soundex -# code, I like undef other people may want to set it to 'Z000'. - -$soundex_nocode = undef; - -sub soundex -{ - local (@s, $f, $fc, $_) = @_; - - push @s, '' unless @s; # handle no args as a single empty string - - foreach (@s) - { - $_ = uc $_; - tr/A-Z//cd; - - if ($_ eq '') - { - $_ = $soundex_nocode; - } - else - { - ($f) = /^(.)/; - tr/AEHIOUWYBFPVCGJKQSXZDTLMNR/00000000111122222222334556/; - ($fc) = /^(.)/; - s/^$fc+//; - tr///cs; - tr/0//d; - $_ = $f . $_ . '000'; - s/^(.{4}).*/$1/; - } - } - - wantarray ? @s : shift @s; -} - -1; - -__END__ - -=head1 NAME - -Text::Soundex - Implementation of the Soundex Algorithm as Described by Knuth - -=head1 SYNOPSIS - - use Text::Soundex; - - $code = soundex $string; # get soundex code for a string - @codes = soundex @list; # get list of codes for list of strings - - # set value to be returned for strings without soundex code - - $soundex_nocode = 'Z000'; - -=head1 DESCRIPTION - -This module implements the soundex algorithm as described by Donald Knuth -in Volume 3 of B<The Art of Computer Programming>. The algorithm is -intended to hash words (in particular surnames) into a small space using a -simple model which approximates the sound of the word when spoken by an English -speaker. Each word is reduced to a four character string, the first -character being an upper case letter and the remaining three being digits. - -If there is no soundex code representation for a string then the value of -C<$soundex_nocode> is returned. This is initially set to C<undef>, but -many people seem to prefer an I<unlikely> value like C<Z000> -(how unlikely this is depends on the data set being dealt with.) Any value -can be assigned to C<$soundex_nocode>. - -In scalar context C<soundex> returns the soundex code of its first -argument, and in list context a list is returned in which each element is the -soundex code for the corresponding argument passed to C<soundex> e.g. - - @codes = soundex qw(Mike Stok); - -leaves C<@codes> containing C<('M200', 'S320')>. - -=head1 EXAMPLES - -Knuth's examples of various names and the soundex codes they map to -are listed below: - - Euler, Ellery -> E460 - Gauss, Ghosh -> G200 - Hilbert, Heilbronn -> H416 - Knuth, Kant -> K530 - Lloyd, Ladd -> L300 - Lukasiewicz, Lissajous -> L222 - -so: - - $code = soundex 'Knuth'; # $code contains 'K530' - @list = soundex qw(Lloyd Gauss); # @list contains 'L300', 'G200' - -=head1 LIMITATIONS - -As the soundex algorithm was originally used a B<long> time ago in the US -it considers only the English alphabet and pronunciation. - -As it is mapping a large space (arbitrary length strings) onto a small -space (single letter plus 3 digits) no inference can be made about the -similarity of two strings which end up with the same soundex code. For -example, both C<Hilbert> and C<Heilbronn> end up with a soundex code -of C<H416>. - -=head1 AUTHOR - -This code was implemented by Mike Stok (C<stok@cybercom.net>) from the -description given by Knuth. Ian Phillips (C<ian@pipex.net>) and Rich Pinder -(C<rpinder@hsc.usc.edu>) supplied ideas and spotted mistakes. |
