One of the things that got a little less clear with A12 was the idea of
multiple C<is> clauses.
Once upon a time, we talked about:
my $spot is Dog is const is persistent is ...;
Obviously some of those are traits, now. However, I'm wondering how to
handle things like my recent suggestion of a class (metaclass instance) that
generated different accessor behavior.
The obvious way was:
use GrammarMod;
# use AccessorClass;
NewKeyword thing {...}
# accessor_class thing {...}
but isn't there a better way? In particular, is there some way for the trait
to declare that it modifies the metaclass, not the class, so that:
use GrammarMod;
# use AccessorClass;
class thing is NewKeyword {...}
# class Obj is accessor_class { has $.foo is rw; }
would be able to change the metaclass behavior, not the class behavior?
At first blush, this is a macro:
class OtherBehavior is MetaClass {...}
# class AccessorClass is MetaClass {...}
macro NewKeyword is parsed(<Perl6::ClassDecl>)
{
$0.meta_class = new OtherBehavior;
}
but then there's the issue of composition.
Perhaps the accessor function behavior is a role, but it seems more like a
MetaRole:
macro NewKeyword is ...
{
$0.meta_class will do OtherRole;
}
Comment?
=Austin
