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From: shebs@utah-orion.UUCP (Stanley Shebs)
Newsgroups: net.lang.lisp
Subject: 3-Lisp
Message-ID: <137@utah-orion.UUCP>
Date: Tue, 8-Jul-86 11:08:14 EDT
Article-I.D.: utah-ori.137
Posted: Tue Jul  8 11:08:14 1986
Date-Received: Wed, 9-Jul-86 02:13:31 EDT
Organization: University of Utah CS Dept
Lines: 26
Keywords: Lisp, 3-Lisp, purity, reflection

There has been some interest in my recent but rather cryptic mention of
the Lisp dialect "3-Lisp".

3-Lisp was first defined in Brian Smith's thesis from MIT in 1982 ("Reflection
and Semantics in a Procedural Language", MIT LCS TR-272).  It's about 500
pages of pretty heavy going, and the Maclisp implementation in the appendix
is too full of bugs to be really useful.  There are papers by Smith in the
84 POPL in Salt Lake City, and in the 84 Lisp conference, where he and Jim
desRivieres show an implementation method.  Xerox PARC Intelligent Systems
Lab report ISL-1 is the reference manual (it's titled the "Interim 3-LISP
Reference Manual, and is also coauthored with Jim desRivieres).  I believe
there are later manuals from either PARC or CSLI, which is where Smith is at
these days.

I have an implementation of 3-Lisp that used to work in PSL, but then
I translated it to Common Lisp, and as of yet have not gotten the
necessary readtable hacking to work yet (3-Lisp requires massive and tricky
changes).  I hope to have it finished sometime this summer (if I can find
the time!).  The implementation has been specially hacked to spill its
guts while running, since reflection is rather a mysterious process, and
one can't really understand it without seeing it in action.  However, it
is ridiculously slow.  A good compiler for 3-Lisp would be very difficult,
since reflection requires that one be able to produce, manipulate, and
re-install the full state of the virtual machine at any time.

								stan