[Swarm-Support] The problem in lispAppArchiver. (concerns saving window geometry & loading parameters)

[Paul Johnson]

About 1 month ago Pietro noticed that the ~/.swarmArchiver file is no 
longer created when we run Swarm-2.2 on Fedora Core Linux.  I'm trying 
to figure that one out, along with some other lisp related troubles.  I 
FEAR that I introduced this problem while hacking Swarm to compile on 
FC5.  But Marcus also suspects that there might be a version related 
wrinkle in gcc and nested functions.

Recently, I tried to run some programs that use scm parameter files, 
such as the ASM and Heatbugs in batch mode.  Both of them fail because 
the global object lispAppArchiver is not able to find "asm.scm" and 
"heatbugs.scm" (respectively). 


For that problem, I've found a solution is to explicitly set the 
parameter file, changing code in Heatbugs like so.  In main.m,

change this method of creating theTopLevelSwarm:

 if ((theTopLevelSwarm = [lispAppArchiver getWithZone: globalZone
                                       key: "batchSwarm"]) == nil)

to this:

id archiver;  
archiver = [LispArchiver create: globalZone
setPath:"/home/pauljohn/swarm/OtherPeoplesCode/swarmapps-objc-2.2-2/heatbugs/heatbugs.scm"];
    theTopLevelSwarm = [archiver getWithZone: globalZone key: 
"batchSwarm"];

   [archiver drop];

if ( theTopLevelSwarm == nil)
      raiseEvent(InvalidOperation,
             "Can't find the parameters to create batchSwarm");

A similar change HeatbugBatchSwarm.m replaces the use of lispAppArchiver 
to a user specified scm file.

After that, "heatbugs -b" runs.


So I started to wonder "what's wrong with lispAppArchiver"? 

I don't think it is being created at all.

Start any swarm model in gdb, and after initSwarm() runs, guess what?

(gdb) print lispAppArchiver
$2 = (struct objc_object *) 0x0


Humph!

What the heck?

Here's one hint.  With the gcc-4.1, it appears to me that compiled 
programs no longer fail when a message is sent to nil.  That's how 
Heatbugs gets so far as it does, the lispAppArchiver is nil but objc 
does not warn  you.

I'm curious to know if anybody has this experience on other platforms, 
or if somebody knows what to do about it?

 
pj    

--
Paul E. Johnson                       email: address@hidden
Professor, Political Science          http://pj.freefaculty.org
1541 Lilac Lane, Rm 504                              
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66044-3177           FAX: (785) 864-5700