View on
MetaCPAN is shutting down
For details read Perl NOC. After June 25th this page will redirect to
dann > Class-Method-Modifiers-Fast > Class::Method::Modifiers::Fast



Annotate this POD


Open  0
View/Report Bugs
Module Version: 0.041   Source  


Class::Method::Modifiers::Fast - provides Moose-like method modifiers


    package Child;
    use parent 'Parent';
    use Class::Method::Modifiers::Fast;

    sub new_method { }

    before 'old_method' => sub {
        carp "old_method is deprecated, use new_method";

    around 'other_method' => sub {
        my $orig = shift;
        my $ret = $orig->(@_);
        return $ret =~ /\d/ ? $ret : lc $ret;


Method modifiers are a powerful feature from the CLOS (Common Lisp Object System) world.

Class::Method::Modifiers::Fast provides three modifiers: before, around, and after. before and after are run just before and after the method they modify, but can not really affect that original method. around is run in place of the original method, with a hook to easily call that original method. See the MODIFIERS section for more details on how the particular modifiers work.


before method(s) => sub { ... }

before is called before the method it is modifying. Its return value is totally ignored. It receives the same @_ as the the method it is modifying would have received. You can modify the @_ the original method will receive by changing $_[0] and friends (or by changing anything inside a reference). This is a feature!

after method(s) => sub { ... }

after is called after the method it is modifying. Its return value is totally ignored. It receives the same @_ as the the method it is modifying received, mostly. The original method can modify @_ (such as by changing $_[0] or references) and after will see the modified version. If you don't like this behavior, specify both a before and after, and copy the @_ during before for after to use.

around method(s) => sub { ... }

around is called instead of the method it is modifying. The method you're overriding is passed in as the first argument (called $orig by convention). Watch out for contextual return values of $orig.

You can use around to:

Pass $orig a different @_
    around 'method' => sub {
        my $orig = shift;
        my $self = shift;
        $orig->($self, reverse @_);
Munge the return value of $orig
    around 'method' => sub {
        my $orig = shift;
        ucfirst $orig->(@_);
Avoid calling $orig -- conditionally
    around 'method' => sub {
        my $orig = shift;
        return $orig->(@_) if time() % 2;
        return "no dice, captain";


Takatoshi Kitano <> gfx




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

syntax highlighting: