tl;dr version: no questions here, just some discoveries that I wanted to spread a little farther and get google-indexed :)
A while back I posted on Stack Overflow about extracting the metaclass of the currently-composing class from within the role definition: http://stackoverflow.com/questions/1758884/how-can-i-access-the-meta-class-of-the-module-my-moose-role-is-being-applied-to ... which lead me to MooseX::Role::Parameterized (a continued two big thumbs up BTW), which lead me to a few discoveries that I wanted to mention here for posterity: 1. $args{consumer} only contains the metaclass of the target class at the first level of parameterization. If the parameterized role (Role::A) is further including another parameterized role (Role::B), then $args{consumer} in Role::B will actually contain the metaclass of the first parameterized role (MooseX::Role::Parameterized::Meta::Role::Parameterized), rather than (a possible subclass of) Moose::Meta::Class. In my application I'm nesting parameterized roles a few levels deep (the code is cleaner this way rather than having lots of nested if statements), so I've added a 'meta' parameter to the list of params being passed around: # when calling the sub-role: role { # isa Moose::Meta::Class my $meta = $args{consumer}; with Role::B => { # other parameters... metaclass => $meta, }; }; # and in the subrole: parameter metaclass => ( is => 'ro', isa => 'Moose::Meta::Class', required => 1, ); role { # isa Moose::Meta::Class my $meta = $params->metaclass; }; 2. $args{consumer} won't even be a metaclass in the case of a role application to a specific object instance -- in this case it will be the type of the object being applied to. role { my $meta = $args{consumer}; $meta = $meta->meta if not $meta->isa('Moose::Meta::Class'); }; Neither of these discoveries seemed obvious at first, so I wanted to pass it on to save others some heartache. I wonder if the "true" metaclass should perhaps be available via some sort of method call, to avoid the backflips I've done above -- I'm using all the code above as boilerplate in all my parameterized roles now. PS. Earlier today I was about to post here asking how one could apply a parameterized role to an object instance (as there was no example in the documentation), but in stepping through the Moose guts I discovered that indeed it is just as simple as for non-parameterized roles: (oh happy day) my $foo = My::Foo->new(); Moose::Util::apply_all_roles($foo, My::Role, { parameter => 'value' });
