How can I access a method of the consumer class inside a method created at runtime in a method of the parameterized role using Moose with Perl?

Question

I define a method inside a parametrized role that needs to create a new class at run time using Moose::Meta::Class->create and apply that exact parametrized role to it. I am also making a new method for that role using

$new_class->meta->add_method( some_name => sub {
 my ($self) = @_;
 ...
})

inside the sub {...} I want to access a method of the consumer class and use it for something, I have tried using $self->get_method, it didn't work, how do I do this?

Please notice that the $self inside the sub above is MooseX::Role::Parameterized::Meta::Role::Parameterizable

I also have another question, if I do this:

my $object = Moose::Meta::Class->create(
       "some_type",

);

Why isn't $object of type some_type and it's some ugly MooseX::Role::Parameterized::Meta::Role::Parameterizable and how do I get to the object of type some_type?

Answer 1

To answer your second question, the reason is because Perl's OO doesn't allow you to add a method to just one instance of a class, so Moose has to fake it by creating a subclass with the extra method and reblessing the unique object into that subclass.

Note that, if you are doing things correctly and doing your introspection with isa, has, and/or does rather than by trying to rely on the name of the object's blessed package, this doesn't matter. The object still isa some_type, has all of some_type's attributes, and does all of some_type's roles even though it's now blessed into a package with an ugly auto-generated name.

Answer 2

It sounds like your underlying problem is nearly exactly what I described at this question: from within the role definition, you need to get at the class (and its meta-class) of the object or class the role is being applied to. This isn't possible from within normal roles, but it's possible through parameterized roles.

Answer 3

I'm not quite sure what you're trying to do here. Let's assume you have

my $new_class = Moose::Meta::Class->create('FooBar');

then $new_class is the meta object for FooBar. So, if you want to add a method to FooBar you would say

$new_class->add_method(foo => sub { … });

which would basically be the same as

FooBar->meta->add_method(foo => sub { … });

You should also probably use find_meta() from Moose::Util. This will return the correct meta object (if there is one) even if your class doesn't have a meta method or it uses it for something else.

As said, I'm not sure this answers your question.