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File::Find::Rule::Extending(3) User Contributed Perl Documentation File::Find::Rule::Extending(3) NAME
File::Find::Rule::Extending - the mini-guide to extending File::Find::Rule SYNOPSIS
package File::Find::Rule::Random; use strict; # take useful things from File::Find::Rule use base 'File::Find::Rule'; # and force our crack into the main namespace sub File::Find::Rule::random () { my $self = shift()->_force_object; $self->exec( sub { rand > 0.5 } ); } 1; DESCRIPTION
File::Find::Rule went down so well with the buying public that everyone wanted to add extra features. With the 0.07 release this became a possibility, using the following conventions. Declare your package package File::Find::Rule::Random; use strict; Inherit methods from File::Find::Rule # take useful things from File::Find::Rule use base 'File::Find::Rule'; Force your madness into the main package # and force our crack into the main namespace sub File::Find::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::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::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. 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 File::Find::Rule::MMagic was the first extension module, so maybe check that out. perl v5.18.2 2011-09-19 File::Find::Rule::Extending(3)
