NAME

Monkey::Patch::Context - Scoped monkeypatching (you can at least play nice)

VERSION

version 0.03.01

SYNOPSIS

use Monkey::Patch::Context qw(:all);

sub some_subroutine {
    my $pkg = patch_class 'Some::Class' => 'something' => sub {
        my $ctx = shift;
        say "Whee!";
        $ctx->{orig_sub}->(@_);
    };
    Some::Class->something(); # says Whee! and does whatever
    undef $pkg;
    Some::Class->something(); # no longer says Whee!

    my $obj = Some::Class->new;
    my $obj2 = Some::Class->new;

    my $whoah = patch_object $obj, 'twiddle' => sub {
        my $ctx  = shift;
        my $self = shift;
        say "Whoah!";
        $ctx->{orig_sub}->($self, @_);
    };

    $obj->twiddle();  # says Whoah!
    $obj2->twiddle(); # doesn't
    $obj->twiddle()   # still does
    undef $whoah;
    $obj->twiddle();  # but not any more

DESCRIPTION

This module is a fork of Monkey::Patch 0.03. Its only notable difference, at the moment, is that the patcher subroutine gets, as the first argument, a context hash instead of the original subroutine. The context hash contains, among others, the original subroutine in orig_sub key. There are other information contained in other keys, like orig_name and possible others in the future. This gives more, well, context to the patcher subroutine, useful e.g. when the same patcher subroutine patches multiple subroutines.

SUBROUTINES

The following subroutines are available (either individually or via :all)

patch_package (package, subname, code)

Wraps package's subroutine named <subname> with your <code>. Your code recieves a context hash (containing these keys: orig_sub which is the original subroutine, orig_name which is the original subroutine's name) as its first argument, followed by any arguments the subroutine would have normally gotten. You can always call the subroutine ref your received; if there was no subroutine by that name, the coderef will simply do nothing.

patch_class (class, methodname, code)

Just like patch_package, except that the @ISA chain is walked when you try to call the original subroutine if there wasn't any subroutine by that name in the package.

patch_object (object, methodname, code)

Just like patch_class, except that your code will only get called on the object you pass, not the entire class.

HANDLES

All the patch functions return a handle object. As soon as you lose the value of the handle (by calling in void context, assigning over the variable, undeffing the variable, letting it go out of scope, etc), the monkey patch is unwrapped. You can stack monkeypatches and let go of the handles in any order; they obey a stack discipline, and the most recent valid monkeypatch will always be called. Calling the "original" argument to your wrapper routine will always call the next-most-recent monkeypatched version (or, the original subroutine, of course).

BUGS

This magic is only faintly black, but mucking around with the symbol table is not for the faint of heart. Help make this module better by reporting any strange behavior that you see!

ORIGINAL AUTHOR

Paul Driver <frodwith@cpan.org>

AUTHOR

Steven Haryanto <sharyanto@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2012 by Steven Haryanto.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.