Sub::HandlesVia::Manual::WithMouse(3pm)

Usage

 package Kitchen {
   use Mouse;
   use Sub::HandlesVia;
   use Types::Standard qw( ArrayRef Str );
   
   has food => (
     is          => 'ro',
     isa         => ArrayRef[Str],
     handles_via => 'Array',
     default     => sub { [] },
     handles     => {
       'add_food'    => 'push',
       'find_food'   => 'grep',
     },
   );
 }

(If you have a mouse in your kitchen, that might not be very hygienic.)

Manual

Sub::HandlesVia allows you to delegate methods from your class to the values of your objects' attributes.

Conceptually, it allows you to define "$object->push_number($n)" to be a shortcut for "$object->numbers->push($n)" except that "$object->numbers" is an arrayref, so doesn't have methods you can call on it like "push".

You should be able to use Sub::HandlesVia as a drop-in replacement for MouseX::NativeTraits, just replacing "traits => ['Array']" in an attribute definition with "handles_via => 'Array'".

Usage in Mouse Roles

Mouse roles are only partially supported.

 package R1 {
   use Mouse:Role;
 }
 
 package R2 {
   use Mouse:Role;
   use Sub::HandlesVia;
   
   # define some attributes with delegation
 }
 
 # This class is broken.
 package C1 {
   use Mouse;
   with 'R1', 'R2';
 }
 
 # This class should work.
 package C2 {
   use Mouse;
   with 'R1';
   with 'R2';
 }

For details, see <https://github.com/tobyink/p5-sub-handlesvia/issues/9>.

Patches to fix the issue are very welcome!

Which Methods Can Be Delegated To?

The "handles_via" option indicates which library of methods should be available. Valid values include Array, Blessed, Bool, Code, Counter, Enum, Hash, Number, Scalar, and String.

An arrayref can be provided for "handles_via", though many of the options are conceptually contradictory.

 handles_via => [ 'Number', 'Scalar' ]

Mouse Native Types

Although the synopsis shows Types::Standard being used for type constraints, Mouse native types should also work fine.

 package Kitchen {
   use Mouse;
   use Sub::HandlesVia;
   
   has food => (
     is          => 'ro',
     isa         => 'ArrayRef[Str]',
     handles_via => 'Array',
     default     => sub { [] },
     handles     => {
       'add_food'    => 'push',
       'find_food'   => 'grep',
     },
   );
 }

True MouseX::NativeTraits Drop-In Syntax

Sub::HandlesVia will also recognize MouseX::NativeTraits-style "traits". It will jump in and handle them before MouseX::NativeTraits notices!

 package Kitchen {
   use Mouse;
   use Sub::HandlesVia;
   
   has food => (
     is          => 'ro',
     isa         => 'ArrayRef[Str]',
     traits      => ['Array'],
     default     => sub { [] },
     handles     => {
       'add_food'    => 'push',
       'find_food'   => 'grep',
     },
   );
 }

Copyright and licence

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

Disclaimer of warranties

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

Releases

3 releases since Debian 12 (Bookworm); the text changed 2 times.