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- Subject: Re: RES: "behavior"
- From: "Steve Donovan" <sjdonova@...>
- Date: Thu, 20 Jan 2005 12:55:41 +0200
>>> email@example.com 01/20/05 05:47AM >>>
> Here is an Objective-C example on how to add "behavior" to another
> class. In a nutshell, a class in Objective-C is simply a structure
> holding methods (aka functions). You can therefore easily move
> (aka "behaviors") from one class to another. So instead of (ab)using
> inheritance, one is more likely to use "composition".
>*Too way* complicated...
Ah, what I liked about Lua is that it's so simple and
elegant compared to C++ - away with the
straightjacket! So Objective C idioms are interesting;
to _move_ a method from one class to another in
Lua is just an assignment, but you need _some_
guarantee about the new self in that case.
For example, a method that expects
its object to quack is not going to work on
anything except a duck.
There are performance constraints on any
OOP implementation. E.g., top of my head; it
would not be difficult to implement properties
transperantly, via __index looking for accessor
functions called 'get_<name>' etc. But that
makes at least property access a good deal
slower than a plain method call. That
may well be acceptable in many cases,
but not all.