1 | ###########################################################################
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2 | #
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3 | # BasPlug.pm -- base class for all the import plugins
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4 | # A component of the Greenstone digital library software
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5 | # from the New Zealand Digital Library Project at the
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6 | # University of Waikato, New Zealand.
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7 | #
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8 | # Copyright (C) 1999 New Zealand Digital Library Project
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9 | #
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10 | # This program is free software; you can redistribute it and/or modify
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11 | # it under the terms of the GNU General Public License as published by
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12 | # the Free Software Foundation; either version 2 of the License, or
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13 | # (at your option) any later version.
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14 | #
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15 | # This program is distributed in the hope that it will be useful,
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16 | # but WITHOUT ANY WARRANTY; without even the implied warranty of
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17 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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18 | # GNU General Public License for more details.
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19 | #
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20 | # You should have received a copy of the GNU General Public License
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21 | # along with this program; if not, write to the Free Software
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22 | # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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23 | #
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24 | ###########################################################################
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25 |
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26 | package BasPlug;
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27 |
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28 | use parsargv;
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29 | use multiread;
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30 | use cnseg;
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31 | use acronym;
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32 | use textcat;
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33 | use strict;
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34 | use doc;
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35 | use diagnostics;
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36 |
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37 | sub print_general_usage {
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38 | my ($plugin_name) = @_;
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39 |
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40 | print STDERR "\n usage: plugin $plugin_name [options]\n\n";
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41 | print STDERR " -input_encoding The encoding of the source documents. Documents will be\n";
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42 | print STDERR " converted from these encodings and stored internally as\n";
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43 | print STDERR " utf8. The default input_encoding is ascii. Accepted values\n";
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44 | print STDERR " are:\n";
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45 | print STDERR " iso_8859_1 (extended ascii)\n";
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46 | print STDERR " Latin1 (the same as iso-8859-1)\n";
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47 | print STDERR " ascii (7 bit ascii -- may be faster than Latin1 as no\n";
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48 | print STDERR " conversion is neccessary)\n";
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49 | print STDERR " gb (GB or GBK simplified Chinese)\n";
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50 | print STDERR " iso_8859_6 (8 bit Arabic)\n";
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51 | print STDERR " windows_1256 (Windows codepage 1256 (Arabic))\n";
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52 | print STDERR " Arabic (the same as windows_1256)\n";
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53 | print STDERR " utf8 (either utf8 or unicode -- automatically detected)\n";
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54 | print STDERR " unicode (just unicode -- doesn't currently do endian\n";
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55 | print STDERR " detection)\n";
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56 | print STDERR " -process_exp A perl regular expression to match against filenames.\n";
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57 | print STDERR " Matching filenames will be processed by this plugin.\n";
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58 | print STDERR " Each plugin has its own default process_exp. e.g HTMLPlug\n";
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59 | print STDERR " defaults to '(?i)\.html?\$' i.e. all documents ending in\n";
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60 | print STDERR " .htm or .html (case-insensitive).\n";
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61 | print STDERR " -block_exp Files matching this regular expression will be blocked from\n";
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62 | print STDERR " being passed to any further plugins in the list. This has no\n";
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63 | print STDERR " real effect other than to prevent lots of warning messages\n";
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64 | print STDERR " about input files you don't care about. Each plugin may or may\n";
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65 | print STDERR " not have a default block_exp. e.g. by default HTMLPlug blocks\n";
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66 | print STDERR " any files with .gif, .jpg, .jpeg, .png, .pdf, .rtf or .css\n";
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67 | print STDERR " file extensions.\n";
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68 | print STDERR " -extract_acronyms Extract acronyms from within text and set as metadata\n\n";
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69 | print STDERR " -extract_langauge Identify the language of the text and set as metadata\n\n";
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70 | }
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71 |
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72 | # print_usage should be overridden for any sub-classes having
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73 | # their own plugin specific options
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74 | sub print_usage {
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75 | print STDERR "\nThis plugin has no plugin specific options\n\n";
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76 |
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77 | }
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78 |
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79 | sub new {
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80 | my $class = shift (@_);
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81 | my $plugin_name = shift (@_);
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82 |
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83 | my $self = {};
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84 | my $encodings = "^(iso_8859_1|Latin1|ascii|gb|iso_8859_6|windows_1256|Arabic|utf8|unicode)\$";
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85 |
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86 | # general options available to all plugins
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87 | if (!parsargv::parse(\@_,
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88 | qq^input_encoding/$encodings/ascii^, \$self->{'input_encoding'},
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89 | q^process_exp/.*/^, \$self->{'process_exp'},
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90 | q^block_exp/.*/^, \$self->{'block_exp'},
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91 | q^extract_acronyms^, \$self->{'extract_acronyms'},
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92 | q^extract_language^, \$self->{'extract_language'},
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93 | "allow_extra_options")) {
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94 |
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95 | print STDERR "\nThe $plugin_name plugin uses an incorrect general option (general options are those\n";
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96 | print STDERR "available to all plugins). Check your collect.cfg configuration file.\n";
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97 | &print_general_usage($plugin_name);
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98 | die "\n";
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99 | }
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100 |
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101 | return bless $self, $class;
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102 | }
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103 |
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104 | # initialize BasPlug options
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105 | # if init() is overridden in a sub-class, remember to call BasPlug::init()
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106 | sub init {
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107 | my $self = shift (@_);
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108 | my ($verbosity) = @_;
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109 |
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110 | # verbosity is passed through from the processor
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111 | $self->{'verbosity'} = $verbosity;
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112 |
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113 | # set process_exp and block_exp to defaults unless they were
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114 | # explicitly set
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115 |
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116 | if ((!$self->is_recursive()) and
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117 | (!defined $self->{'process_exp'}) || ($self->{'process_exp'} eq "")) {
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118 |
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119 | $self->{'process_exp'} = $self->get_default_process_exp ();
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120 | if ($self->{'process_exp'} eq "") {
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121 | warn ref($self) . " Warning: Non-recursive plugin has no process_exp\n";
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122 | }
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123 | }
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124 |
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125 | if ((!defined $self->{'block_exp'}) || ($self->{'block_exp'} eq "")) {
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126 | $self->{'block_exp'} = $self->get_default_block_exp ();
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127 | }
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128 |
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129 | # handle input_encoding aliases
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130 | $self->{'input_encoding'} = "iso_8859_1" if $self->{'input_encoding'} eq "Latin1";
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131 | $self->{'input_encoding'} = "windows_1256" if $self->{'input_encoding'} eq "Arabic";
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132 | }
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133 |
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134 | sub begin {
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135 | my $self = shift (@_);
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136 | my ($pluginfo, $base_dir, $processor, $maxdocs) = @_;
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137 | }
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138 |
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139 | sub end {
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140 | my ($self) = @_;
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141 | }
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142 |
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143 | # this function should be overridden to return 1
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144 | # in recursive plugins
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145 | sub is_recursive {
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146 | my $self = shift (@_);
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147 |
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148 | return 0;
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149 | }
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150 |
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151 | sub get_default_block_exp {
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152 | my $self = shift (@_);
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153 |
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154 | return "";
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155 | }
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156 |
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157 | sub get_default_process_exp {
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158 | my $self = shift (@_);
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159 |
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160 | return "";
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161 | }
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162 |
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163 | # The BasPlug read() function. This function does all the right things
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164 | # to make general options work for a given plugin. It calls the process()
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165 | # function which does all the work specific to a plugin (like the old
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166 | # read functions used to do). Most plugins should define their own
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167 | # process() function and let this read() function keep control.
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168 | #
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169 | # recursive plugins (e.g. RecPlug) and specialized plugins like those
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170 | # capable of processing many documents within a single file (e.g.
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171 | # GMLPlug) should normally implement their own version of read()
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172 | #
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173 | # Return number of files processed, undef if can't process
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174 | # Note that $base_dir might be "" and that $file might
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175 | # include directories
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176 |
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177 | sub read {
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178 | my $self = shift (@_);
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179 | my ($pluginfo, $base_dir, $file, $metadata, $processor, $maxdocs) = @_;
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180 |
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181 | if ($self->is_recursive()) {
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182 | die "BasPlug::read function must be implemented in sub-class for recursive plugins\n";
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183 | }
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184 |
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185 | my $filename = &util::filename_cat($base_dir, $file);
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186 | return 0 if $self->{'block_exp'} ne "" && $filename =~ /$self->{'block_exp'}/;
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187 | if ($filename !~ /$self->{'process_exp'}/ || !-f $filename) {
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188 | return undef;
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189 | }
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190 | my $plugin_name = ref ($self);
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191 | $file =~ s/^[\/\\]+//; # $file often begins with / so we'll tidy it up
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192 |
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193 | # create a new document
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194 | my $doc_obj = new doc ($filename, "indexed_doc");
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195 |
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196 | # read in file ($text will be in utf8)
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197 | my $text = "";
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198 | $self->read_file ($filename, \$text);
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199 |
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200 | if ($text !~ /\w/) {
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201 | print STDERR "$plugin_name: ERROR: $file contains no text\n" if $self->{'verbosity'};
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202 | return 0;
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203 | }
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204 |
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205 | # include any metadata passed in from previous plugins
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206 | # note that this metadata is associated with the top level section
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207 | $self->extra_metadata ($doc_obj, $doc_obj->get_top_section(), $metadata);
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208 |
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209 | # do plugin specific processing of doc_obj
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210 | return undef unless defined ($self->process (\$text, $pluginfo, $base_dir, $file, $metadata, $doc_obj));
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211 |
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212 | # do any automatic metadata extraction
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213 | $self->auto_extract_metadata ($doc_obj);
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214 |
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215 | # add an OID
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216 | $doc_obj->set_OID();
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217 |
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218 | # process the document
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219 | $processor->process($doc_obj);
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220 |
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221 | return 1; # processed the file
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222 | }
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223 |
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224 | # returns undef if file is rejected by the plugin
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225 | sub process {
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226 | my $self = shift (@_);
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227 | my ($textref, $pluginfo, $base_dir, $file, $metadata, $doc_obj) = @_;
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228 |
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229 | die "Basplug::process function must be implemented in sub-class\n";
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230 |
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231 | return undef; # never gets here
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232 | }
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233 |
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234 | # uses the multiread package to read in the entire file pointed to
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235 | # by filename and loads the resulting text into $$textref. Input text
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236 | # may be in any of the encodings handled by multiread, output text
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237 | # will be in utf8
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238 | sub read_file {
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239 | my $self = shift (@_);
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240 | my ($filename, $textref) = @_;
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241 |
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242 | $$textref = "";
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243 |
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244 | open (FILE, $filename) || die "BasPlug::read_file could not open $filename for reading ($!)\n";
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245 |
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246 | if ($self->{'input_encoding'} eq "ascii") {
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247 | undef $/;
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248 | $$textref = <FILE>;
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249 | $/ = "\n";
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250 | } else {
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251 | my $reader = new multiread();
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252 | $reader->set_handle ('BasPlug::FILE');
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253 | $reader->set_encoding ($self->{'input_encoding'});
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254 | $reader->read_file ($textref);
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255 |
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256 | if ($self->{'input_encoding'} eq "gb") {
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257 | # segment the Chinese words
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258 | $$textref = &cnseg::segment($$textref);
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259 | }
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260 | }
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261 |
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262 | close FILE;
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263 | }
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264 |
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265 | # add any extra metadata that's been passed around from one
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266 | # plugin to another.
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267 | # extra_metadata uses add_utf8_metadata so it expects metadata values
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268 | # to already be in utf8
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269 | sub extra_metadata {
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270 | my $self = shift (@_);
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271 | my ($doc_obj, $cursection, $metadata) = @_;
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272 |
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273 | foreach my $field (keys(%$metadata)) {
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274 | # $metadata->{$field} may be an array reference
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275 | if (ref ($metadata->{$field}) eq "ARRAY") {
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276 | map {
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277 | $doc_obj->add_utf8_metadata ($cursection, $field, $_);
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278 | } @{$metadata->{$field}};
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279 | } else {
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280 | $doc_obj->add_utf8_metadata ($cursection, $field, $metadata->{$field});
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281 | }
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282 | }
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283 | }
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284 |
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285 | # extract acronyms (and hopefully other stuff soon too).
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286 | sub auto_extract_metadata {
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287 | my $self = shift (@_);
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288 | my ($doc_obj) = @_;
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289 |
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290 | if ($self->{'extract_acronyms'}) {
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291 | my $thissection = $doc_obj->get_top_section();
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292 | while (defined $thissection) {
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293 | my $text = $doc_obj->get_text($thissection);
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294 | $self->extract_acronyms (\$text, $doc_obj, $thissection) if $text =~ /./;
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295 | $thissection = $doc_obj->get_next_section ($thissection);
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296 | }
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297 | }
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298 |
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299 | if ($self->{'extract_language'}) {
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300 | my $thissection = $doc_obj->get_top_section();
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301 | while (defined $thissection) {
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302 | my $text = $doc_obj->get_text($thissection);
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303 | $self->extract_language (\$text, $doc_obj, $thissection) if $text =~ /./;
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304 | $thissection = $doc_obj->get_next_section ($thissection);
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305 | }
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306 | }
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307 |
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308 | }
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309 |
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310 |
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311 | # Identify the language of a section and add it to the metadata
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312 | sub extract_language {
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313 | my $self = shift (@_);
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314 | my ($textref, $doc_obj, $thissection) = @_;
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315 |
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316 | # remove all HTML tags
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317 | my $text = $$textref;
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318 | $text =~ s/<P[^>]*>/\n/sgi;
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319 | $text =~ s/<H[^>]*>/\n/sgi;
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320 | $text =~ s/<[^>]*>//sgi;
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321 | $text =~ tr/\n/\n/s;
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322 |
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323 | # get the language
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324 | my @results = textcat::classify($text);
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325 | @results = ("unknown") if ($#results > 2);
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326 |
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327 | my $language = join(" or ", @results);
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328 | $doc_obj->add_utf8_metadata($thissection, "Language", $language);
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329 | print "Language: $language\n";
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330 |
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331 | }
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332 |
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333 | # extract acronyms from a section in a document. progress is
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334 | # reported to STDERR based on the verbosity. both the Acronym
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335 | # and the AcronymKWIC metadata items are created.
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336 |
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337 | sub extract_acronyms {
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338 | my $self = shift (@_);
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339 | my ($textref, $doc_obj, $thissection) = @_;
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340 |
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341 | print STDERR " checking for acronyms ...\n"
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342 | if ($self->{'verbosity'} >= 2);
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343 |
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344 | my $acro_array = &acronym::acronyms($textref);
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345 |
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346 | foreach my $acro (@$acro_array) {
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347 |
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348 | #check that this is the first time ...
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349 | my $seen_before = "false";
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350 | my $previous_data = $doc_obj->get_metadata($thissection, "Acronym");
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351 | foreach my $thisAcro (@$previous_data) {
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352 | if ($thisAcro eq $acro->to_string())
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353 | {
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354 | $seen_before = "true";
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355 | print STDERR " already seen ". $acro->to_string() . "\n"
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356 | if ($self->{'verbosity'} >= 2);
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357 | }
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358 | }
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359 |
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360 | if ($seen_before eq "false")
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361 | {
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362 | #do the normal acronym
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363 | $doc_obj->add_utf8_metadata($thissection, "Acronym", $acro->to_string());
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364 | print STDERR " adding ". $acro->to_string() . "\n"
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365 | if ($self->{'verbosity'} >= 1);
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366 |
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367 | # do the KWIC (Key Word In Context) acronym
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368 | my @kwic = $acro->to_string_kwic();
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369 | foreach my $kwic (@kwic) {
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370 | $doc_obj->add_utf8_metadata($thissection, "AcronymKWIC", $kwic);
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371 | print STDERR " adding ". $kwic . "\n"
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372 | if ($self->{'verbosity'} >= 2);
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373 | }
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374 | }
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375 | }
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376 | print STDERR " done with acronyms. \n"
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377 | if ($self->{'verbosity'} >= 2);
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378 | }
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379 |
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380 | 1;
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