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\F1\CFeb 6, 1980





Dr. Alan Perlis
Computer Science Department
Yale University
New Haven, CO  06520


Dear Dr. Perlis:

\JI enjoyed your remarks at the ADA debate last week. I agree that,
though LISP is not perfect, it does have a lot to tell people about
the construction of large, complex programs and systems. Besides the 
traditional applications in AI, the LISP machine project at MIT has 
shown the viability of LISP as a systems language. Of course, too
many people still think of LISP as a toy for processing lists; whereas
production LISPs have all the trappings of a general purpose programming
language.

Where LISP shines is the programming environment; it was quite discouraging
to see the lack of understanding  of environments, both within the audience
and as depicted on the ADA Stoneman slide. It does seem that an understanding
of the "environmental issues" only comes from exposure. Alas, most people
have not even programmed in LISP, let alone programmed in an interactive
environment (glass teletypes not included).

Two
 difficulties have been the lack of accurate information about LISP
and the lack of powerful, inexpensive systems which could support interactive
programming.
In recent years, 
I have been trying to remedy these defficiencies. \F5Anatomy of LISP\F1
attempts to supply a reasonable text about LISP ideas without
becoming a programming manual. Then, with the growing personal computer group
becoming enamored of Pascal, I wrote an editorial for BYTE (March 1979), for
it disturbed me to see them moving from Basic to Pascal without considering
what else was available, and without considering what they were giving up.
In spite of UCSD Pascal, you and I know Pascal is still a batch processing language.

From the BYTE editorial, I expanded to the August issue on LISP.
One beneficial effect from that effort is a LISP users/interest group
that I have formed. Putting my money where my mouth is, I formed The LISP
Company, (T .(L . C)). We have completed a version of the MIT LISP machine 
LISP that runs on a Z-80; and run it does, suprisingly enough! The task
was akin to building a model of the Eiffel tower in a  bottle.
Alas, we have only implemented the language segment of the system; I am
presently trying to round up funding to do the hardware for the envrionment.
We are also exploring the sixteen-bit machines --a more suitable
host for LISP. All this takes money, and money is expensive.

Between writing funding proposals,
 I am writing an introductory LISP text, and organizing the LISP Conference
for this summer. Particularly after seeing the pervasiveness of the ADA
syndrome, it seems important to offer a strong (and almost anthetical)
altenative. So far, LISP is the most  likely umbrella. I hope that
this summer's conference can help to enlarge that umbrella  before 
the POPL world follows the pied piper of ADA too far.
I think your remarks last week did a lot to stem that trend. I would
be most grateful if you could send me a copy of your prepared
remarks. I could use all the ammunition I can get.

I am enclosing a notice or two for the up-coming LISP Conference;
I sincerely hope you can attend.
For your interest,
I am also enclosing a description of the first release of our LISP.
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Yours sincerely,


John R. Allen
Founder, The LISP Company
18215 Bayview Dr.
Los Gatos Ca, 95030
(408) 353-3857

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