Sat Aug 15 12:02:16 CEST 2009

More sharing between Scheme and PF

There is already quite some duplication, mostly in exception handling,
GC, and printing.  This should be handled by "mem". (mom?).

I guess it's a good idea to factor out as much as possible beforehand.

Let's rename "mem" to "base", which implements:

      - GC restart
      - primitive leaf types
      - primtiive exception handling
      - printing

Hmm..  Let's not.  The simplest way is to make sure the primitives
themselves will take from the base class.  This can be factored out
later.. It was only a couple of lines to add the ABORT exceptions in
PF + it's slightly different since the interpreter is not re-entrant.