Re: [GD-General] RE: Ruby

[Brian H. <bri...@py...>]

At 08:00 PM 12/27/2001 -0800, Jesse Jones wrote:
>BTW one of the really cool things about Ruby is that classes aren't closed.

Same with Obj-C.  You can extend an existing class, sans source code, by 
creating a "category".

@interface ClassToExtend (NewMethods)
- ( int ) newMethod;
@end

You then implement them in a separate implementation area (just like 
regular Obj-C classes), and from that point on you can call those new 
methods directly on the object:

ClassToExtend *c = [[ClassToExend alloc] init];

int i = [c newMethod]; //Call "newMethod" on a class that I didn't write

You can only change the interface, not the implementation, since changing 
the latter would cause a change in the class' size.  There can be some 
problems with name collisions if you're not careful.

Brian