Re: GNUstep <-> Cocoa compatibility

[Fred Kiefer]

Hi Artem,

due to the festive season trafic on this mailing list is a bit low, so I 
try to answer your mail until somebody with more experiance in the 
Cocoa-GNUstep porting is available again. Keep in mind that I don't have 
access to an Apple MacOSX computer!

Artem Baguinski wrote:
> since the year have grown old and a new one is approaching i decided to
> learn some new computer toolketry... 
>
> it's not the first time I consider to learn GNUstep - i saw presentation
> of [i guess Adam] at the first FOSDEM (when it still was called OSDEM)
> and was quite facinated by the Objective-C and Foundation/GNUstep base.
> But i haven't had an opprtunity to use it after - alas. 
I think Adam was giving his great talk on the second FOSDEM, but never 
mind.

> As i understood from documents, Cocoa and GNUstep are both
> implementations of OpenStep but Cocoa being proprietary (?)
> implementation evolves while GNUstep tries to be nice. Does that mean
> GNUstep application may have problems running on MAC OS X and using
> Cocoa libraries? 
This depends on what you want to do. If you just take the GNUstep code 
and suply a new NIB file for MacOSX not many problems should be 
expected. Even better, if you write your Application with Renaissance, 
than it is protable right from the start.
If you on the other hand want to use the GNUstep GUI on top of MacOSX 
there are still some problems to be expected.

Porting the other way, from Cocoa to GNUstep may be more difficult as 
Cocoa has further evoloved and you may easyly be using classes more 
methods that are not available for GNUstep.

> Another question is how consistent the interface of GNUstep application
> is when run in Cocoa environment? As I figured from this month's mails
> in the archive the widgets have to draw themselves, does this mean
> GNUstep windows will look very different from "native" cocoa windows, or
> will the gnustep application use "native" widgets when built and run to
> use cocoa libraries?
See above. Best thing is to only transfer the code.

> Are there any applications out there that look equally consistent when
> run in WindowMaker + GNUstep environment and aqua + cocoa?