Re: Allegro Coral Common LISP

[Leslie Kaelbling <Kaelbling@warbucks.ai.sri.com>]

I've been using Allegro CL on a MacII with 4mb of memory and an 80mb
hard disk.  All of my code is pure CommonLisp, so I can carry diskettes
back and forth from work (on a Symbolics) to home.  I only had to make two
changes in a large language compiler:  the default *print-case* is
lower, so some atoms I was synthesizing came out in lower case, and I
was using some LONG filenames with the "|" character in them for
intermediate files that didn't agree with the MAC file system.  Other
than that, there were no problems.  

Porting graphical applications is another story, however.  Allegro CL
provides a nice interface to the MAC windowing system, but it is
radically different from the Symbolics system and requires a major
effort to do a port.  One of the biggest problems is the lack of
automatic mouse-sensitive regions.  

The system has been very nicely designed and implemented.  The debugger
is quite weak, but the editor (Fred Resembles Emacs Deliberately) is
easy to use and customize.  One amazing thing about this system is that
IT NEVER CRASHES.  Even when you write buggy mouse handlers, it keeps
going.  I have found a couple of bugs in the course of using the
compiler (you get an error if you try to look 2^31 up in a hashtable),
but nothing serious.

It is technically possible to use Allegro CL with 1 meg of memory, but
all it does is thrash.  I'm very comfortable with 4 meg for development,
but I am still unable to run my compiler on very large programs without
it thrashing.  Until real virtual memory is available, I don't think
this is a feasible system for heavy-duty use.  Rumor has it that Apple
is working on a new version of their OS (not AUX) that will have virtual
memory, so maybe this problem will be fixed soon.

If anyone has any specific questions, I'd be happy to try to answer
them.

Leslie Kaelbling