I'm working on a class that is a test-bed of sorts, and I want to explore some good way to provide for "plug in" behavior.

In Perl6, you have a but keyword that will dynamically apply a role to an instance, without having to name a new class for it and create the instance of that type.

I saw some clues in the manual the Moose might do this even though it doesn't offer syntactic sugar for it. Is there a good way to do this directly (as opposed to messing with MOP directly)?

That is, can Moose add a role ("traits") to an instance after it has been created, as opposed to having to declare a derived class that is based on the original class and adds the role as well? I'm thinking that one "plug in" might need to add roles to several collaborating objects, as well as do more mundane things with those object's APIs.

Catalyst, for example, lets you specify some extensions as arguments to new. Along the lines I'm thinking, the BUILD routine can slurp them in.

In reply to Extensions via Moose by John M. Dlugosz

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