Walter: extend existing classes with new methods?

[Marcio]

Chris Nicholson-Sauls wrote:
> Okay... maybe I'm missing something here?  

   Yes, you are.


> I was pretty sure we already 
> do have this, in a little OOP concept called inheritance?  

   Nope.

 > Given a
> library defining 'class Foo', if I need custom behavior, I simply define 
> a 'class MyFoo:Foo' and voila!
> 
> Or is there some deeper concept that I'm overlooking entirely?
> 


   You want String to have a new method, say asURL. Or findReplace. Or 
whatever. Not a new String subclass. You want to add functionality to 
String.

   You want all objects to understand dumpOn (aStream). Say you are 
writing a persistent framework. You need to add methods to Object.

   If you ever used Smalltalk, you'd know what I mean.

marcio