GNUstep and MacOS X Port Effort (fwd)

[Stefan Urbanek]

Hi,

Just to let you know, that there is an ongoing discussion about porting Swarm 
to GNUstep (and OSX) on swarm-support list (see forwarded message). I think, 
GNUstep will only benefit from this 'marriage of projects', because Swarm has 
already a large userbase.

Stefan

---------- Forwarded message ----------
Date: 2002-10-03 13:49:37 +0200
From: W.Northcott@unsw.edu.au
Subject: GNUstep and MacOS X Port Effort

As I result of a general lack of interest some weeks back, I got to be 
coordinator for the MacOS X port.

There seeems to have been much fairly enthusiastic discussion amongst various 
programmers regarding the merits of rewriting Swarm on the GNUstep foundation.

I considered it might be appropriate at this point to try and summarise the 
GNUstep port idea together with its implications for a MacOS X port and some 
indication of a desired outcome and the way it might be achieved. Others could 
then express their thoughts and hopefully we could reduce the project to a 
number of tasks that I might put up on the Savannah site in substitution for 
the existing MacOS X outline.

I see this as attempt to focus people's thoughts as an aid to action rather 
than some effort to put forward my view of the issues.

1.  Motivation
As Marcus has pointed out, a few years back it looked like Objective-C was a 
dead language.  As a result various decisions were made to modify low level 
components of the language and roll these into Swarm.  This appeared to be the 
best course of action at the time.
The situation has now changed.  Apple is shipping millions of Objective-C based 
computers and interest in GNUstep has revived.  Apple are spending big 
development dollars on Objective-C and most of their work which is relevant to 
Swarm is opensource.
It no longer makes sense for Swarm to roll its own Objective-C runtime, doing 
so makes Swarm very hard to install on MacOS X or GNU step and fails to take 
advantage of development work on the language and Foundation class libraries 
which has been carried out by others.
For the avoidance of doubt, I use the word 'runtime' to refer to the C function 
library which implements the guts of ObjC message passing etc and the ObjC 
program which defines the root object - NSObject on MacOS X and GNUstep.  It is 
my impression that only this program should make C function calls into the 
runtime library.

2.  Objectives (Wish list) in no particular order
a. Swarm should be simple to install on any 'standard' GNUstep or MacOS X 
system.  Other than GNUstep the only other non-standard item should be hdf5 if 
it is required.
b.  To facilitate the above, Swarm should not make any C calls into the 
'runtime'.
c.  The phasic object system should be preserved and possiby elaborated.
d.  The GNUstep/Cocoa classes should provide the GUI eliminating dependence on 
Tcl/Tk/BLT
e.  As many basic classes as possible should come from the standard libraries, 
to maximise the benefit from work done by others.
f.  Wherever possible existing APIs should be supported even if deprecated for 
new modelling.

3.  Observations
a.  Marcus has observed that the purpose of the mframe stuff in the runtime is 
to support the link between Java and ObjC.  GNUstep and Cocoa already contain 
such a link.  Indeed Apple has put a lot of development effort into this.  We 
should use this and scrap mframe which is a nasty machine specific klugeTM.
b.  Being totally Gatesophobic, I have no idea how this plays on Windoze. Is 
there a workable Cygwin/GNUstep installation available?
c.  The above scenario is based on a possibly unfounded belief that GNUstep and 
MacOS X/Cocoa have a large degree of source code compatability at the level we 
would require for Swarm.  Any comments?
d.  Method functions are incompatable with the above objectives as well as 
being abhorrent to any OO believer.  They should be given a decent burial.
e.  On the MacOS X front, none of the above removes the need to get a basic 
Swarm on XFree86 running as a learning exercise.
f.  The root object of Swarm is Object which maybe can be built by extending 
NSObject, which makes the above at least faintly plausible.

Please comment/abuse/destroy.

Bill Northcott



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