Comment utiliser les rappels avec Text :: Perl de Perl?

Question

#!/usr/local/bin/perl 
use warnings; 
use 5.012; 
use Text::Document; 
use Text::DocumentCollection; 

my $c = Text::DocumentCollection->new(file => 'coll.db' ); 

my $doc_one = Text::Document->new(lowercase => 0, compressed => 0); 
my $doc_two = Text::Document->new(lowercase => 0, compressed => 0); 
my $doc_three = Text::Document->new(lowercase => 0, compressed => 0); 

$doc_one->AddContent('foo bar biz buu muu muu'); 
$doc_two->AddContent('foo foofoo Foo foo'); 
$doc_three->AddContent('one two three foo foo'); 

$c->Add('key_one', $doc_one); 
$c->Add('key_two', $doc_two); 
$c->Add('key_three', $doc_three); 

Quelqu'un pourrait-il me montrer un exemple de fonction de rappel raisonnable et compréhensible?

#!/usr/local/bin/perl 
use warnings; 
use 5.012; 
use Text::Document; 
use Text::DocumentCollection; 

my $c = Text::DocumentCollection->NewFromDB(file => 'coll.db'); 

my @result = $c->EnumerateV(\&Callback, 'the rock'); 
say "@result"; 

sub Callback { 
    ... 
    ... 
} 

# The function Callback will be called on each element of the collection as: 
# my @l = CallBack($c, $key, $doc, $rock); 
# where $rock is the second argument to Callback. 
# Since $c is the first argument, the callback may be an instance method of Text::DocumentCollection. 
# The final result is obtained by concatenating all the partial results (@l in the example above). 
# If you do not want a result, simply return the empty list(). 

Answer 1

Dans la fonction EnumerateV, la fonction de rappel est appelée pour tous les documents de la collection, et les valeurs de retour de chaque appel de la fonction de rappel sont collectés et renvoyés. Il y a probablement une façon assez simple et équivalente d'écrire cela en utilisant la fonction map.

Dans tous les cas, voici un exemple fonction de rappel pour vos données d'échantillon:

sub document_has_twice { 
    # return document key if term appears twice in the document 
    my ($collection_object, $key, $document, $search_term) = @_; 
    if ($document->{terms}{$search_term} 
      && $document->{terms}{$search_term} >= 2) { 
     return $key; 
    } 
    return; 
} 

my @r = $c->EnumerateV(\&document_has_twice, "foo"); 
print "These documents contain the word 'foo' at least twice: @r\n"; 

@r = $c->EnumerateV(\&document_has_twice, "muu"); 
print "These documents contain the word 'muu' at least twice: @r\n"; 

@r = $c->EnumerateV(\&document_has_twice, "stackoverflow"); 
print "These documents contain the word 'stackoverflow' at least twice: @r\n"; 

---

Sortie:

These documents contain the word 'foo' at least twice: key_three key_two 
These documents contain the word 'muu' at least twice: key_one 
These documents contain the word 'stackoverflow' at least twice: