[ruby-talk:16445] Re: Ruby - Objective C - GNUstep

On Wed, 13 Jun 2001, Laurent Julliard wrote:

> If I understand what you said you'd like to "rewrite" NSMutableString,
> NSMutableArray, and NSMutableDictionary in Ruby right? Why is it better
> to do that rather than simply map the GNUStep objects in Ruby? 

No... those three classes are actually "class clusters" - the superclasses
are abstract and implement everything but a few primitives; there are
private subclasses that implement the primitives and actually get
instantiated (which particular subclass gets used at any time is usually
decided internally by the framework).  I was suggesting that we write
subclasses of these, in Objective-C, that implement the necessary
primitives through operations on the equivalent Ruby objects - this would
allow pretty transparent passing back and forth between the two
frameworks.  However, that doesn't work for immediate values (which need
to be converted between the Ruby types and the C types, not a big deal),
or for other classes (which would need some kind of a forwarding proxy
object; I have that working calling Obj-C from Ruby, but not the other way
around yet).

As a sort of side issue that intrigues me somewhat - an object in
Objective-C is simply a struct with an "isa" pointer to its Class as the
first field.  I'm curious what could be done by modifying ruby.h to
include such a field in all objects, so that a ruby VALUE pointer can be
cast directly to an Objective-C object.

> PS: Do you have some code that we could share now?

Not much of it.  You can look at http://beta4.com/~avi/cupertino.tgz
You'll probably have to tweak the GNUMakefile to get it to build on your
system.