Re: [Swarm-Support] development priorities (was Re: Membership inSwarm Developmen Group)

[Marcus G. Daniels]

Bill Northcott wrote:
> With the resurgence of Apple from a basket case to one of the most 
> profitable companies in the computer business, Objective-C is really 
> not marginal.  It is very much alive. The compiler problems really are 
> history.  Also the convergence between Apple and GNU versions has made 
> it a lot more portable.  Phases might be seen as an issue because they 
> will be outside the ken of thousands of new Objective-C programmers 
> brought up on Cocoa/GNUStep. 
Extensive surgery would be needed in Defobj, but it *could* be done to 
move to the new Apple runtime.   The -fobjc-direct-dispatch could solve 
some performance problems.  I think something extra would need to be 
done to keep the CPU branch predictor working well, though.   Maybe 
Apple is thinking about that, I have no idea.

What are the benefits we seek with keeping Objective C alive?   Is it 
mainly a port of Swarm that works really well on MacOS X, esp with 
XCode, together with a uniform working version for existing users?  (I 
don't mean to denigrate that goal, but others might be more interested 
in dynamic dispatch features or something.)

As I understand it, C++ wasn't used for the prototypes of Swarm because 
it was considered incomplete and hard to learn.  However, there does now 
exist Objective C++.  In principle performance sensitive parts of models 
could be rewritten in C++ style and Swarm and dynamic parts would remain 
using Objective C message dispatch and objects.   Probably sounds pretty 
Frankenstein, but I think it is pretty straightforward in terms of 
layering the Objective C compiler and runtime on the GCC C++ parts 
instead of on the C parts.  A person wouldn't necessarily have to use 
C++ or even realize the change of compiler even occurred.