Re: [Swarm-Support] Followup: found work-aroundfor missing~/swarmarchiver.scm too

[Marcus G. Daniels]

Bill Northcott wrote:
> The existing way, before Marcus' recent change, of having some compile 
> time option for the library behaviour seems to be appropriate, but 
> even that should be documented. 
It's just a matter of putting a:

id nil_method (id obj, SEL sel) { return nil; }

..into a Swarm app.. if for some reason you wanted to remain ignorant of 
messages to nil.

I've helped to debug many Swarm models, and usually when people send a 
message to nil, it's because they forgot to fully implement 
buildObjects.  Thus when messages to nil are tolerated, some part of 
their model is just off, and they may not realize it until they've run a 
bunch of experiments only to find their time has been wasted.

Having an abort for this behavior may defy expectations of some 
Objective C programmers, but at least it will be clear it is defiance.   
These folks, being savvy Objective C programmers, will know the 
nil_method override trick.  

Swarm also does Java, and so here the underlying Objective C code is 
just a means to an end.   Java users will expect null pointer exceptions.