On Sat, Nov 05, 2005 at 11:35:38AM -0800, Jonathan Lang wrote:
: First off: is there a way to declare a method as being private to a role?
We're still batting around the notion of private methods. Certainly
with a lexically scoped sub you can get most of the same benefit.
Trust could then perhaps simply be exportation of the sub to another
scope, though naming another lexical scope is problematic, and if
you export into a package the name becomes public property. So the
import needs to be into a different lexical scope that happens to be
governed by a particular trusted class name.
Lexically scoped methods or submethods are also a syntactic possibility:
my method foo {...}
my submethod BUILD {...}
If this is how you write private methods, though, these have to be
totally invisible to the ordinary dispatcher.
And just as has defaults to private in the absence of a twigil, perhaps
it does on methods too:
has $foo; # short form private
has $!foo; # long form private (but same variable as $foo)
has $.foo; # public virtual interface to private $!foo
has method foo; # short form private?
has method !foo;# long form private?
has method .foo;# public? same as method foo
But that's a little strange--has should probably indicate that
each object maintains its own copy. Maybe it's really the underlying
delegation mechanism:
has method foo = some_other_foo(); # init at BUILD time
So probably my is still better for private methods, and tends to
keep weirdness out of the package's public interface. It would be
nice if the package only contains public method names and private
metadata is confined to the meta object (whether class or proto based).
: Second: can a role reclassify as private a method that is composed
: into it from another role?
I don't see much point. Private methods are non-virtual, and
shouldn't be inherited, or block the inheritance of anything public.
Private methods are really just subs in disguise. We allow them
to be called with something resembling ordinary dispatch syntax
(probably via $!foo and $obj!foo() these days) but the public and
private dispatch mechanisms have no overlap.
Larry
