[net.micro.mac] ExperLisp Comments Sought

evans@mhuxt.UUCP (crandall) (05/10/85)

A call to ExperTellience yesterday indicated that they were shipping
their Lisp for the Macintosh. The claim was that it is Common Lisp.
They are also working on some expert system tools. Has anyone played
with ExperLisp in either its beta-site or final forms? Is it useful
(somehow I have my doubts...)?

				Steve Crandall
				ihnp4!mhuxt!evans

jwp@utah-cs.UUCP (John W Peterson) (05/11/85)

I had a chance to play with it, and, although I didn't play with it
extensivly, I was pretty impressed.  While it doesn't implement "full
commom Lisp" (something about as nebulous as "full Ada") it definitly
implements enough of the language to write genuinly useful programs.

In addition to vanilla Lisp, they provide very complete access to
toolbox functions from within the Lisp environment.  You can define your
own menus, create and manipulate windows, use the mouse, etc.  In
addition to all the quickDraw graphics, they supply something called
"bunny graphics"  This is like turtle graphics, but it also works in 3D
and spherical coordinates.

Allthough I didn't time it, execution seems pretty fast.  The system
doesn't have an interpreter in the normal sense; all functions are
compliled as they are defined.  While this keeps things fast and compact,
it does restrict your ability to munge on defined functions.

The system is big, you must have a two-drive mac with at least 512K to run it.
It does leave quite a chunk of heap space though, in fact ExperTelligence
claims the OPS5 production system is running on it.

It isn't perfect though, I've heard reports that it does occasionally
bomb. While the manual is well written, it is very poorly organized
(functions in alphabetical order...like the old TECO manuals...).  They
supply a multi-window editor environment for program development.
However, the editor *does not support paren bouncing*.  This is a real
lose if you're used to that feature.  There are no data-structuring
tools (e.g., DefStruct), though they claim to have an Objects package on
the way.   It's also very spendy, >$500.  (Sort of like Jazz... you
pretty well have to get the company to pay for it...)

[I can't resist a plug:  For those with less than $500 or less than 512K,
Macintosh PSL (Portable Standard Lisp) should be available Real Soon Now.
And unlike ExperLisp, we implemented paren matching, and our manual
has an index! : ) ]

kentb@tekchips.UUCP (Kent Beck) (05/11/85)

I have a copy of ExperLisp version 1.0 (the released version).  I am
immensely pleased with it.  As Lisps go it is fairly complete, with most of
the utility functions I expect.  It includes hooks for you to create your
own menus, or change the ones that are there.  You can also create and
resize windows.  All the Toolbox graphics calls are there, which to my way
of thinking is the best thing about the package.  The only problem I had was
that I had an animation that was allocating two regions every time through a
tight loop and I eventually crashed the machine.  The problem is that you
can't use the Macintosh data types like you use the Lisp data types.  I
think ExperTelligence did the right thing by not trying to make Mac data
looke like Lisp data.  It's a little bit of a pain, but I'd rather have
things out there where I can see them.  By the way I called ET about my
crash and ended up talking to the president of the company.  He assured me
that version 1.0.2 had fixed the problem and would exit gracefully and
promised to send an update disk right away.  I haven't received it yet, but
it was only 5 days ago.

Bottom line: good Lisp, great graphics, pretty good interface.  Worth $500?
Maybe.

Kent L. Beck
kentb@tektronix
tektronix!tekchips!kentb

jwp@utah-cs.UUCP (John W Peterson) (05/12/85)

Oops, in my previous review of ExperLisp I claimed they hadn't implemented
DefStruct.  This isn't true; they do have a limited implementation of CL
defstruct.