Testing the role of Elk in non Moose

Question

let's say you have a Moose class that requires an attribute that fulfills the role:

package MyMooseClass;
use Moose;

has 'a' => ( does => 'MyRole' );

Now I would like to create an instance of MyMooseClass as follows:

my $instance = MyMooseClass->new( { a => $a_non_moose_stuff } );

Where $ a_non_moose_stuff is an instance of the non-moose class, but implements the required role methods.

Is there a way to get Moose to check that my $ a_non_moose_stuff matches the role, even if it is not implemented using Moose?

Answer 1

The easiest way is to use duck_type instead of a role to test your interface. Duck_type is a looser restriction, basically duck_type is just a list of methods that objects are expected to have. For instance:

package MyMooseClass;
use Moose;
use Moose::Util::TypeConstraints qw/duck_type/;

has 'a' => (
  isa => duck_type(qw/method1 method1 some_other_method/),
);

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my $instance = MyClass->new(param1=>'val1', param2=>'val2');

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