Callback::Cleanup - Declare callbacks that clean themselves up

	use Callback::Cleanup;

	my $anon_sub = callback {
		# this is the sub body
	} cleanup {
		# this is called on DESTROY
	}

	# or

	Callback::Cleanup->new(
		sub { }, # callback
		sub { }, # cleanup
	);

This is a very simple module that provides syntactic sugar for callbacks that need to finalize somehow.

Callbacks are very convenient APIs when they have no definite end of life. If an end of life behavior is required this helps keep the cleanup code and callback code together.

callback BLOCK $cleanup

cleanup BLOCK $callback

Both of these exports act as the identity function when given only one parameter.

When given enough arguments they will create a Callback::Cleanup object.

This means that you can declare a callback with a cleanup like this:

	my $cleans_up = callback {

	} cleanup {

	}

Or a derived sub that cleans up an existing subref:

	my $cleans_up = cleanup {

	} \&needs_cleanup;

As well as a few other useless forms.

In perl code references that are not closures aren't garbage collected (they are shared).

This module uses clone_if_immortal in Sub::Clone to make sure timely destruction of these callbacks happens.

Yuval Kogman <nothingmuch@woobling.org>

	Copyright (c) 2006, 2008 the aforementioned authors. All rights
	reserved. This program is free software; you can redistribute
	it and/or modify it under the same terms as Perl itself.