NAME
File::Find::Object::Rule::Extending - the mini-guide to extending File::Find::Object::Rule
SYNOPSIS
package File::Find::Object::Rule::Random;
use strict;
use warnings;
# take useful things from File::Find::Object::Rule
use base 'File::Find::Object::Rule';
# and force our crack into the main namespace
sub File::Find::Object::Rule::random () {
my $self = shift()->_force_object;
$self->exec( sub { rand > 0.5 } );
}
1;DESCRIPTION
File::Find::Object::Rule inherits File::Find::Rule's extensibility. It is now possibile to extend it, using the following conventions.
Declare your package
package File::Find::Object::Rule::Random;
use strict;
use warnings;Inherit methods from File::Find::Object::Rule
# take useful things from File::Find::Object::Rule
use base 'File::Find::Object::Rule';Force your madness into the main package
# and force our crack into the main namespace
sub File::Find::Object::Rule::random () {
my $self = shift()->_force_object;
$self->exec( sub { rand > 0.5 } );
}Yes, we're being very cavalier here and defining things into the main File::Find::Object::Rule namespace. This is due to lack of imaginiation on my part - I simply can't find a way for the functional and oo interface to work without doing this or some kind of inheritance, and inheritance stops you using two File::Find::Object::Rule::Foo modules together.
For this reason try and pick distinct names for your extensions. If this becomes a problem then I may institute a semi-official registry of taken names.
Taking no arguments.
Note the null prototype on random. This is a cheat for the procedural interface to know that your sub takes no arguments, and so allows this to happen:
find( random => in => '.' );If you hadn't declared random with a null prototype it would have consumed in as a parameter to it, then got all confused as it doesn't know about a '.' rule.
NOTES ABOUT THE CALLBACK
The callback can access the File::Find::Object::Result using $self->finder->item_obj().
AUTHOR
Richard Clamp <richardc@unixbeard.net>
COPYRIGHT
Copyright (C) 2002 Richard Clamp. All Rights Reserved.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
SEE ALSO
File::Find::::Rule::MMagic was the first extension module for File::Find::Rule, so maybe check that out.