From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mikael Djurfeldt <mdj@mdj-pc.nada.kth.se>
To: Jim Blandy <jimb@red-bean.com>
Cc: djurfeldt@nada.kth.se
Subject: Re: guile and emacs
Date: Wed, 08 Sep 1999 14:30:00 -0000
Message-id: <xy7d7vtxfdb.fsf@mdj-pc.nada.kth.se>
References: <199908281821.OAA14563@raeburn.org> <npogfdfa9d.fsf@zwingli.cygnus.com>
X-SW-Source: 1999-q3/msg00005.html

Jim Blandy <jimb@red-bean.com> writes:

> For example, note that the code below is incorrect in Emacs.  Assume
> all functions return Lisp_Object values:
> 
> 	foo (bar (), baz ())
> 
> Suppose the compiler calls bar first, then baz.  While baz runs, foo's
> frame holds a reference to bar's return value --- possibly the only
> one.  If collection can occur in baz, then bar's return value will be
> collected.  Instead, you must write:
> 
> 	{
> 	  Lisp_Object temp = Qnil;
> 	  GCPRO1 (temp);
> 
> 	  temp = bar ();
> 	  foo (temp, baz ());
> 	}
> 
> But for anyone who has not worked on both Guile and Emacs, these
> arguments are anecdotal, and the usual way of thinking about program
> design suggests the opposite conclusion.  So I don't know what to do.
> Any suggestions?

I think sharing your experience with precise vs conservative GC is one
important thing.  We could also try to sift the archives for
discussions on this topic.

I think it would be a really big mistake to settle for an interface
compatible with precise GC if the problems with conservative GC are
just phantoms.