On Wed, 2004-01-07 at 00:43, Jonathan Lang wrote:
> Maybe as an alternative to
>
> role Stringify {must stringify();}
> sub print_it (Stringify $thingie) {print $thingie.stringify();}
>
> you might be able to say
>
> sub print_it ($thingie must stringify()) {print $thingie.stringify();}
>
> Hmm... there's a certain elegance to being able to specify one or two
> requirements directly in a signature.
I'm not sure that works so well in practice. You're explicitly asking
for a method with a particular name when you're ought to be asking for a
method with a particular meaning. That is, if you said:
method threaten ( $thingie must bark() ) { ... }
passing in a Tree object would work, when what you really want something
that does Doggish things, like a Dog, an Actor in a dog costume, or a
RobotDog.
Promoting role names to a position of typishness allows roles to express
the semantics and context of method names that method names alone can't
express uniquely.
Yikes, now I sound like Larry.
<Larry>Or maybe not.</Larry>
-- c
