Re: Swarm and GNUstep

[Marcus G. Daniels]

Paul E Johnson wrote:

> I'm trying to figure why Swarm has its own libobjc.  I've compared the 
> header files of Swarm's libobjc files and the gcc-3.0.4 and the 
> differences are minor.

libobjc is in Swarm for three reasons.

  1) Historically, Cygwin has not included the Objective C compiler or 
the runtime.
      Because it was necessary to pull the runtime into the Java 
environment, it
      was going to be necessary to have it on hand in order to link it 
into a DLL.  
      (Unlike the Unix shared library model, Windows DLLs are fully 
resolved links.)

  2) There have been small but significant fixes for the sake of 64 bit 
systems like
      Tru64 in the Swarm copy of the libobjc runtime.   Packaging 
libobjc with Swarm
      was an easy way to provide control over such things, e.g. when 
the fix was fragile
      and potentially bounded to known usages in Swarm.

  3) At the time, Objective C was pretty much dead.  Apple has brought 
Objective C
      back to life to some extent, and it would now make sense to 
identify the
      fixes and feed them back into the mainline (when there isn't an 
alternative fix in the
      modern sources).  Note, the mframe code lives in the Swarm copy 
of libobjc,
      and would need to be merged with GNUstep, if it still has that
      (again, there are a number of Swarm-private changes to that code, 
which was taken
      from an old, stale codebase).   mframe is used for taking apart 
forwarded call frames
      for resending to Java by FCall.

There should be no problem merging Swarm with GNUstep, since the 
Objective C data structures are the same.  Note, however, that the 
phase-oriented programming model is different enough that in practice it 
would be no more `natural' to use GNUstep Objecitve C than  Java.


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