On Thursday, October 3, 2002, at 03:18 PM, Paul Johnson wrote:
>> (As a lame aside, are we going to have a concept of "private" vs.
>> "protected" vs. "public", or just private/public?
>
> No protected. Even Stroustrup admits it was a mistake in D&E.
Oh, thank God. I was hoping people would say that.
OK, for an entirely different thread...
Is there an accepted preliminary syntax for OO delegation? (I've
looked and can't find anything definitive.) By "delegation", I mean
two different things (you can tell OO programming has firmly arrived by
the fact that, Babel-like, no group of people can ever agree on the
meaning of any given term, making all conversations painful).
1) Delegation through inheritance:
(a.k.a. "mixin" classes, "hard delegation", "concrete interfaces",
etc., etc.)
Example: I want to say that a class DataManager has the capabilities
of the interfaces DataStrategy and CacheStrategy, but is not strictly a
"subclass" of either. In other languages, this might appear like:
class DataManager implements DataStrategy, CacheStrategy { ... }
- or -
class DataManager mixin DataStrategy, CacheStrategy { ... }
(yes, I know you probably wouldn't do a Manager/Strategy like that.
it's just an example, and my mind is blanking right now...)
2) Delegation through attribute:
(a.k.a.... "soft delegation", "instance-based delegation", etc., etc.)
The ability to specify that, if an instance of an object DataSnippet
is affiliated with a specific, runtime instance of a DataManager, e.g.
class DataSnippet {
attr $data_manager is DataManager;
}
... then [some, all] public methods of $self.data_manager can
automatically be delegated by the DataSnippet to that specific
instance, eliminating the need for code that makes you want
to kill yourself:
method foo (...) { $self.data_manager.foo( ... ) }
method bar (...) { $self.data_manager.bar( ... ) }
# ... repeat until carpel tunnel syndrome sets in ...
I have no *good* syntax proposals for this, I don't think I've ever
seen the problem solved with syntax that I really ever liked.
MikeL
