Algorithm::AhoCorasick::SearchMachine - implementation and low-level interface of Algorithm::AhoCorasick

Version 0.03

 use Algorithm::AhoCorasick::SearchMachine;

 sub callback {
     my ($pos, $keyword) = @_;

     ...

     return undef;
 }

 $machine = Algorithm::AhoCorasick::SearchMachine->new(@keywords);

 while (<STDIN>) {
     $machine->feed($_, \&callback);
 }

The constructor. Takes the list of keywords as parameters (there must be at least one, and the constructor dies if they contain an empty string).

Feeds input to the state machine. First (after the instance) argument of this method is the input text (which can be empty, in which case the method doesn't do anything), second argument is the callback invoked on each match. feed calls the callback with 2 arguments: the position and the matched keyword. The callback can stop further search by returning a true value, which feed returns. If the search wasn't stopped, feed returns undef, and can then be called with another chunk of input text to continue the search (matching all keywords, even those spanning multiple chunks). Note that when the callback stops the search, this scenario doesn't work (because the state machine gets out of sync); feed should not be called again on the same instance after the callback returned true. Also note that the position passed to the callback is relative to the current input text chunk; it is negative for keywords spanning multiple chunks.

Vaclav Barta, <vbar@comp.cz>

Copyright 2010 Vaclav Barta, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.