The London Perl and Raku Workshop takes place on 26th Oct 2024. If your company depends on Perl, please consider sponsoring and/or attending.


MooseX::CurriedDelegation - Curry your delegations with methods


This document describes version 0.003 of MooseX::CurriedDelegation - released November 09, 2016 as part of MooseX-CurriedDelegation.


    use Moose;
    use MooseX::CurriedDelegation;

    has one => (is => 'ro', isa => 'Str', default => 'default');

    has foo => (

        is      => 'rw',
        isa     => 'TestClass::Delagatee', # has method curried()
        default => sub { TestClass::Delagatee->new },

        handles => {

            # method-curry
            #   Note the hashref, not arrayref, we employ
            #   first arg is the remote method to delegate to
            #   second is an arrayref comprising:
            #       coderef to call as a method on the instance, followed by
            #       "static" curry args
            # so, essentially:
            #   $self->foo->remote_method($self->$coderef(), @remaining_args);
            # foo_del_one => {
            #   remote_method => [ sub { ... }, qw{ static args } ],
            # },

            foo_del_one => { curried => [ sub { shift->one }, qw{ more curry args } ] },

            # curry_to_self() always returns: sub { shift }
            foo_del_two => { other_method => [ curry_to_self ] },


Method delegation is awfully handy -- but sometimes it'd be awfully handier if it was a touch more dynamic. This is an attribute trait that provides for a delegated method to be curried.


Using this package will cause the relevant attribute trait to be applied without requiring further intervention. We use the standard

    handles => { local_method => delegate_info, ... }

delegation methodology, however our currying is invoked when delegate_info is a hashref. We expect delegate info to look like:

    { remote_method => [ $coderef, @more_curry_args ] }

Only $coderef is ever executed by the delegation. This means that it is safe to have any number of additional coderefs in @more_curry_args: they will be passed through to remote_method without additional manipulation.


In addition, we export a number of helper functions.


This function always returns a coderef like "sub { shift }". That is, this:

    local => { remote => [ curry_to_self ] }

is equivalent to:

    local => { remote => [ sub { shift } ] }

is equivalent to:




Resolves out to the full name of our attribute trait; you can use it as:

    has foo => (traits => [CurriedDelegation], ...)


Please see those modules/websites for more information related to this module.


Please report any bugs or feature requests on the bugtracker website

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.


Chris Weyl <>

I'm a material boy in a material world

Please note I do not expect to be gittip'ed or flattr'ed for this work, rather it is simply a very pleasant surprise. I largely create and release works like this because I need them or I find it enjoyable; however, don't let that stop you if you feel like it ;)

Flattr, Gratipay, or indulge my Amazon Wishlist... If and *only* if you so desire.


This software is Copyright (c) 2012 by Chris Weyl.

This is free software, licensed under:

  The GNU Lesser General Public License, Version 2.1, February 1999