Не знаех за Module::Pluggable, оказва се удобно решение.
Това е кратък пример, ако не съм обяснил добре, питай.

командите са в bold:
files in the testing dir `ls -R`

.:

MyParser  MyParser.pm  test.pl

./MyParser:

Plugin

./MyParser/Plugin:

A.pm  B.pm

cat test.pl

#!/usr/bin/perl



use strict;

use warnings;

use MyParser;

my $obj = MyParser->new({});



### praktichnoto w plugin abstrakciqta:

$obj->parse("tovA e teST");



cat MyParser

package MyParser;



use Module::Pluggable require => 1;



sub new {

  my $class = shift;

  my $self  = shift;



  bless $self, $class

}



sub parse {

  my $self   = shift;

  my $string = shift;



  for my $plugin ($self->plugins) {

    $plugin->parse($string);

  }

}



1;



cat MyParser/Plugin/A.pm

package MyParser::Plugin::A;



sub new {

  my $class = shift;

  my $self  = shift;



  bless $self, $class

}



sub parse {

  my $self = shift;

  my $data = shift;



  print "plyginyt '" . __PACKAGE__ . "' implementira lowercase: " . lc $data . "\n";

}



1;



cat MyParser/Plugin/B.pm

package MyParser::Plugin::B;



sub new {

  my $class = shift;

  my $self  = shift;



  bless $self, $class

}



sub parse {

  my $self = shift;

  my $data = shift;



  print "plyginyt '" . __PACKAGE__ . "' implementira uppercase: " . uc $data . "\n";



}



1;