MooseX::Clone::Meta::Attribute::Trait::Clone - The attribute trait for deeply cloning attributes


version 0.06


    # see MooseX::Clone

    has foo => (
        traits => [qw(Clone)],
        isa => "Something",

    $object->clone; # will recursively call $object->foo->clone and set the value properly


This meta attribute trait provides a clone_value method, in the spirit of get_value and set_value. This allows clone methods such as the one in MooseX::Clone to make use of this per-attribute cloning behavior.


Deriving this role for your own cloning purposes is encouraged.

This will allow your fine grained cloning semantics to interact with MooseX::Clone in the Right™ way.



Whether or not Data::Visitor should be used to clone arbitrary structures. Objects found in these structures will be cloned using clone_object_value.

If true then non object values will be copied over in shallow cloning semantics (shared reference).

Defaults to false (all reference will be cloned).


A hash ref used to construct clone_visitor. Defaults to the empty ref.

This can be used to alter the cloning behavior for non object values.


The Data::Visitor::Callback object that will be used to clone.

It has an object handler that delegates to clone_object_value and sets tied_as_objects to true in order to deeply clone tied structures while retaining magic.

Only used if clone_only_objects is false and the value of the attribute is not an object.


clone_value $target, $proto, %args

Clones the value the attribute encapsulates from $proto into $target.

clone_value_data $value, %args

Does the actual cloning of the value data by delegating to a clone method on the object if any.

If the object does not support a clone method an error is thrown.

If the value is not an object then it will not be cloned.

In the future support for deep cloning of simple refs will be added too.

clone_object_value $object, %args

This is the actual workhorse of clone_value_data.

clone_any_value $value, %args

Uses clone_visitor to clone all non object values.

Called from clone_value_data if the value is not an object and clone_only_objects is false.


יובל קוג'מן (Yuval Kogman) <>


This software is copyright (c) 2008 by יובל קוג'מן (Yuval Kogman).

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