No, I think Java interfaces are a kluge to get around copying a broken type system and the lack of multiple inheritance.
Multiple Inheritance != Protocols | Interfaces
I quite agree, but I've done enough Java to know that if they could have "solved" it with MI, they would have.
Protocols/Interfaces is a way of saying "My structure is none of your damn business, but I comply with the rules you've set."
Yes, exactly.
I disagree, and I hope you've simply swapped terms around.
I think you want to declare "I comply with ruleset X" at the callee object level. That enables the compiler to (1) check that you're not lying; and (2) optimize based on (1).
At least one of us is using "caller/callee" in the X11 sense. What I mean and what I think you mean is:
method foo ( Thingie $t ) { ... }
$object->foo( $behaves_like_thingie );
foo() says, "Give me something that I can treat like a Thingie. I don't care HOW it does it, I just want it to do something sane."
$behaves_like_thingie is an instance of a class that somehow says, "Hey, I act like Thingie. I'm substitutable for Thingie if you don't break my encapsulation."
If we're just confused over a bit of terminology, we're in violent agreement on the idea, which is much more important.
-- c
