/usr/share/perl5/Lingua/Stem/Snowball/Da.pm is in liblingua-stem-snowball-da-perl 1.01-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 | package Lingua::Stem::Snowball::Da;
use strict;
use bytes;
# -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2,
# *NOT* "earlier versions", as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
# -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
#####
use constant DEBUG=>0;
use vars qw(%cache $VERSION);
$Lingua::Stem::Snowball::Da::VERSION = 1.01;
# special characters
my $aa = chr(229); # å
my $ae = chr(230); # æ
my $oe = chr(248); # &oring;
# delete the s if a "s ending" is preceeded by one
# of these characters.
my %s_ending = (
a => 1,
b => 1,
c => 1,
d => 1,
f => 1,
g => 1,
h => 1,
j => 1,
k => 1,
l => 1,
"m" => 1,
n => 1,
o => 1,
p => 1,
r => 1,
t => 1,
v => 1,
"y" => 1,
z => 1,
$aa => 1,
);
# danish vowels.
my $vowels = "aeiouy$ae$aa$oe";
my %vowels = (
a=>1,
e=>1,
i=>1,
o=>1,
u=>1,
"y"=>1,
$ae=>1,
$aa=>1,
$oe=>1,
);
# ####
# the endings in step 1
# XXX: these must be sorted by length
# to save time we've done it already.
my @endings = (
["erendes"],
["erende", "hedens"],
["erens", "endes", "heden", "ethed", "ernes", "erets", "heder", "erede"],
["ende", "enes", "ered", "eren", "erer", "eres", "eret", "erne", "heds"],
["hed", "ers", "ene", "ere", "ens", "ets"],
["er", "es", "et", "en"],
["e"],
);
%Lingua::Stem::Snowball::Da::cache = ();
sub new {
my $pkg = shift;
$pkg = ref $pkg || $pkg;
my %arg = @_;
my $self = {};
bless $self, $pkg;
$self->{USE_CACHE} = $arg{use_cache} || 0;
return $self;
}
sub step1 {
my ($rs, $word) = @_;
# ### STEP 1
my $endinglen = 8;
foreach (@endings) {
$endinglen--;
my $endingw = substr($rs, -$endinglen); # do this once.
foreach (@$_) {
# only continue if the word has this ending at all.
next unless $endingw eq $_;
warn "matched $_ in $word" if DEBUG;
# a) delete the ending.
return substr($word, 0, -$endinglen);
}
}
if (substr($rs, -1) eq 's') { # b)
# check if it has a valid "s ending"...
if ((length $rs == 1) ?
exists $s_ending{substr($word, -2, -1)} :
exists $s_ending{substr($rs, -2, -1)}) {
warn "Valid s eding $word" if DEBUG;
# ...delete the last character (which is a s)
return substr($word, 0, -1);
}
}
return $word;
}
sub stem {
my ($self, $word) = @_;
my $orig_word;
warn " --- start : $word ---" if DEBUG;
if ($self->{USE_CACHE}) {
$orig_word = $word;
return $cache{$word} if defined $cache{$word};
}
my ($rs, $lslen, $rslen) = getsides($word);
return $word unless $lslen >= 3;
$word = step1($rs, $word);
# ### STEP 2
warn "Step 2" if DEBUG;
($rs, $lslen, $rslen) = getsides($word);
return $word unless $lslen >= 3;
if (substr($rs, -2) =~ /gd|dt|gt|kt/) {
warn "delete last letter $word in step 2" if DEBUG;
$word = substr($word, 0, - 1);
($rs, $lslen, $rslen) = getsides($word);
return $word unless $lslen >= 3;
}
# ### STEP 3
if (substr($rs, -4) eq "igst") {
warn "st as in igst deleted in $word" if DEBUG;
$word = substr($word, 0, -2);
($rs, $lslen, $rslen) = getsides($word);
return $word unless $lslen >= 3;
}
if (substr($rs, -4) eq "l${oe}st") {
warn "t as in l${oe}st deleted in $word" if DEBUG;
$word = substr($word, 0, -1);
($rs, $lslen, $rslen) = getsides($word);
return $word unless $lslen >= 3;
}
for (qw/elig lig els ig/) {
my $len = length;
if (substr($rs, -$len) eq $_) {
warn "delete $_ in $word" if DEBUG;
$word = substr($word, 0, -$len);
($rs) = getsides($word);
if (substr($rs, -2) =~ /gd|dt|gt|kt/) {
warn "delete last letter $word in step 2 again" if DEBUG;
$word = substr($word, 0, - 1);
($rs, $lslen, $rslen) = getsides($word);
}
last;
}
}
return $word unless $lslen >= 3 && length $word > 3;
# ### STEP 4
if ($word =~ /([^$vowels])\1$/o) {
warn "delete double konsonant in $word" if DEBUG;
$word = substr($word, 0, -1);
}
if ($self->{USE_CACHE}) {
$cache{$orig_word} = $word;
}
warn " --- end : $word ---" if DEBUG;
return $word;
}
sub getsides {
my $word = shift;
# ###
# find the first vowel with a non-vowel after it.
my($found_vowel, $nonv_position, $curpos) = (0, -1, 0);
#$found_vowel = 1 if exists $vowels{substr($word,0,1)};
foreach (split//, $word) {
$curpos++;
if (exists $vowels{$_}) {
$found_vowel = 1;
next;
} elsif ($found_vowel) {
$nonv_position = $curpos;
last;
}
}
# got nothing: return false
return undef if $nonv_position == -1;
my($rs, $lslen); # left side and right side.
# ###
# length of the left side must be atleast 3 chars.
if ($nonv_position < 3) {
$lslen = length substr($word, 0, 3);
$rs = substr($word, 3);
} else {
$lslen = $nonv_position;
$rs = substr($word, $nonv_position);
}
return($rs, $lslen, length $rs);
}
1;
__END__
=head1 NAME
Lingua::Stem::Snowball::Da - Porters stemming algorithm for Denmark
=head1 SYNOPSIS
use Lingua::Stem::Snowball::Da
my $stemmer = new Lingua::Stem::Snowball::Da (use_cache => 1);
foreach my $word (@words) {
my $stemmed = $stemmer->stem($word);
print $stemmed, "\n";
}
=head1 DESCRIPTION
The stem function takes a scalar as a parameter and stems the word
according to Martin Porters Danish stemming algorithm,
which can be found at the Snowball website: L<http://snowball.tartarus.org/>.
It also supports caching if you pass the use_cache option when constructing
a new L:S:S:D object.
=head2 EXPORT
Lingua::Stem::Snowball::Da has nothing to export.
=head1 AUTHOR
Dennis Haney E<lt>davh@davh.dkE<gt>
Ask Solem Hoel, E<lt>ask@unixmonks.netE<gt> (Swedish version)
=head1 SEE ALSO
L<perl>. L<Lingua::Stem::Snowball>. L<Lingua::Stem>. L<http://snowball.tartarus.org>.
=cut
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