package Lingua::YALI::Examples;
# ABSTRACT: Examples of usages.
# VERSION



__END__
=pod

=head1 NAME

Lingua::YALI::Examples - Examples of usages.

=head1 VERSION

version 0.011_1

=head1 Introduction

Basic information about YALI package can be found at L<Lingua::YALI|Lingua::YALI>.

This documentation introduces the most important commands for using YALI package.

=head2 Preparation

In this documentation we will be using texts from L<Wikipedia|http://www.wikipedia.org/>.
So we start with downloading 20 articles for Czech, English, and French.

    # download data
    for i in `seq 1 20`; do
        id=`printf "%02d" $i`;
        echo "Processing document $id";
        lynx --dump 'http://en.wikipedia.org/wiki/Special:Random' -noprint --nolist --nonumbers --nomargins -width=10000 > eng.$id.txt;
        lynx --dump 'http://cs.wikipedia.org/wiki/Special:Random' -noprint --nolist --nonumbers --nomargins -width=10000 > ces.$id.txt;
        lynx --dump 'http://fr.wikipedia.org/wiki/Special:Random' -noprint --nolist --nonumbers --nomargins -width=10000 > fra.$id.txt;
    done;

    # create list of files for training
    ls ces.* | head -n15 > list.ces.train;
    ls eng.* | head -n15 > list.eng.train;
    ls fra.* | head -n15 > list.fra.train;
    
    # create list of files for testing
    ls ces.* | tail -n5 > list.ces.test;
    ls eng.* | tail -n5 > list.eng.test;
    ls fra.* | tail -n5 > list.fra.test;

=head1 Scripts

This section provides information how to use scripts L<yali-builder|Lingua::yali-builder>, L<yali-identifier|Lingua::yali-identifier>, and  L<yali-language-identifier|Lingua::yali-language-identifier>.

=head2 Language Identification  with Pretrained Models

The script yali-language-identifier is distributed with pretrained 
language models for L<122 languages|Lingua::YALI::LanguageIdentifier/LANGUAGES>.

    # check out possible options
    yali-language-identifier --help

    # language identification for Czech
    # option --filelist
    yali-language-identifier -l="eng ces fra" --filelist=list.ces.test
    
    # language identification for English files with different output format
    # option -f (--format)
    yali-language-identifier -l="eng ces fra" --filelist=list.eng.test -f=all_p
    
    # language identification for French files read from STDIN
    # --filelist is equal to -
    cat list.fra.test | yali-language-identifier -l="eng ces fra" --filelist=- -f=tabbed
    
    # identify only single file
    # option -i (--input)
    yali-language-identifier -l="eng ces fra" -i=ces.20.txt -f=all
    
    # single file read from STDIN
    # option -i is equal to -
    cat eng.20.txt | yali-identifier -l="eng ces fra" -i=- -f=all_p

    # single file read from STDIN
    # when --filelist or --input is not used then it is equal to -i=-
    cat fra.20.txt | yali-identifier -l="eng ces fra" -f=all_p

=head2 Building Your Own Models

If you have texts from specific domain it is worth to train your own models on texts from this domain to achieve higher accuracy.

Options C<--filelist> and C<--input> has same meaning as options for L</"Language Identification  with Pretrained Models">.

    # check out possible options
    yali-builder --help
    
    # create Czech bigram model with only 5 most frequent bigrams stored
    # option -n (--ngram) for specifying n-gram size to 2
    # option -c (--count) for storing only 5 most frequent bigrams
    # option -o (--output) for specifying output file name 
    yali-builder --filelist=list.ces.train -n=2 -c=5 -o model.2.5.ces.gz
    
    # create English bigram model with all bigrams stored
    # option -c is ommited that means all   
    cat list.eng.train | yali-builder --filelist=- -n=2 -o model.2.5.eng.gz
    
    # create French bigram model with only 5 most frequent bigrams stored
    # option -i=- means that all training files are read from STDIN
    cat list.eng.train | xargs cat | yali-builder -i=- -n=2 -c=5 -o model.2.5.fra.gz
    
    # create list with models
    # list of models in format class1[TAB]path-to-model is required for identification
    echo -e "ces\tmodel.2.5.ces.gz" > list.models.2
    echo -e "eng\tmodel.2.5.eng.gz" >> list.models.2
    echo -e "fra\tmodel.2.5.fra.gz" >> list.models.2

=head2 Language Identification  with Your Own Models

Only two changes are required to the commands presented in section L<Language Identification  with Pretrained Models>.

=over

=item * Change I<yali-language-identifier> to I<yali-identifier>.

=item * Change I<-l="eng ces fra"> to I<-c=list.models.2>.

=back

    # language identification for Czech files
    yali-identifier -c=list.models.2 -filelist=list.ces.test
    
    # language identification for English files with different output format
    yali-identifier -c=list.models.2 -filelist=list.eng.test -f=all_p
    
    # language identification for French files read from STDIN
    cat list.fra.test | yali-identifier -c=list.models.2 -filelist=- -f=tabbed
    
    # single file
    yali-identifier -c=list.models.2 -i=ces.20.txt -f=all
    
    # single file read from STDIN
    cat eng.20.txt | yali-identifier -c=list.models.2 -i=- -f=all_p

    # single file read from STDIN
    cat fra.20.txt | yali-identifier -c=list.models.2 -f=all_p

=head1 Modules

This section provides information how to use modules L<Lingua::YALI::LanguageIdentifier|Lingua::YALI::LanguageIdentifier>, L<Lingua::YALI::Builder|Lingua::YALI::Builder>, and L<Lingua::YALI::Identifier|Lingua::YALI::Identifier>.

=head2 Language Identification with Your Own Models

This example shows how to detect languages with L<Lingua::YALI::LanguageIdentifier|Lingua::YALI::LanguageIdentifier>.

    use Lingua::YALI::LanguageIdentifier;
    
    # create identifier and register languages
    my $identifier = Lingua::YALI::LanguageIdentifier->new();
    $identifier->add_language("ces", "eng", "fra");
    
    # identify string
    my $result_s = $identifier->identify_string("CPAN, the Comprehensive Perl Archive Network, is an archive of modules written in Perl.");
    
    print "The most probable language is " . $result_s->[0]->[0] . ".\n";
    # prints out The most probable language is eng.
    
    # identify file
    my $result_f = $identifier->identify_file("ces.01.txt");

    print "The most probable language is " . $result_f->[0]->[0] . ".\n";
    # hopefully prints out The most probable language is ces.

    # identify file handle
    open(my $fh, "<:bytes", "fra.01.txt");
    my $result_h = $identifier->identify_handle($fh);

    print "The most probable language is " . $result_h->[0]->[0] . ".\n";
    # hopefully prints out The most probable language is fra.     

=head2 Training Your Own Models

This example shows how to train language models with L<Lingua::YALI::Builder|Lingua::YALI::Builder>.

    use Lingua::YALI::Builder;
    use File::Glob;
    use Carp;
    
    # read file with training files    
    for my $file (File::Glob::bsd_glob("list.*.train")) {
        my @p = split(/\./, $file);
        my $lang = $p[1];

        print STDERR "Building model for $lang\n";

        # create builder for 2-grams
        my $builder = Lingua::YALI::Builder->new(ngrams=>[2]);

        open(my $fh_train, "<", $file) or croak($file . "\n" . $!);
        while ( my $f = <$fh_train> ) {
            chomp $f;
            
            # train on file
            $builder->train_file($f);
        }
        
        # store trained model
        $builder->store("model.".$lang.".gz", 2);
        print STDERR "\tDONE\n";
    }

=head2 Using Your Own Models

This example shows how to use trained language models with L<Lingua::YALI::Identifier|Lingua::YALI::Identifier>.

    use Lingua::YALI::Identifier;
    use File::Glob;
    use Carp;
    
    # load models
    my $identifier = Lingua::YALI::Identifier->new();
    $identifier->add_class("ces", "model.ces.gz");
    $identifier->add_class("eng", "model.eng.gz");
    $identifier->add_class("fra", "model.fra.gz");
    
    # identify string    
    my $result_s = $identifier->identify_string("CPAN, the Comprehensive Perl Archive Network, is an archive of modules written in Perl.");    
    print "The most probable language is " . $result_s->[0]->[0] . ".\n";
    # prints out The most probable language is eng.
    
    # identify all testing files 
    for my $file (File::Glob::bsd_glob("list.*.test")) {
        open(my $fh_train, "<", $file) or croak($file . "\n" . $!);
        while ( my $f = <$fh_train> ) {
        
            chomp $f;
            # identify file
            my $result_f = $identifier->identify_file($f);
            print $f . "\t" . $result_f->[0]->[0] . "\n";
        }
    }

=head1 AUTHOR

Martin Majlis <martin@majlis.cz>

=head1 COPYRIGHT AND LICENSE

This software is Copyright (c) 2012 by Martin Majlis.

This is free software, licensed under:

  The (three-clause) BSD License

=cut

