Subject: Re: Why some people think that Scheme is not a Lisp
From: (Rob Warnock)
Date: Wed, 10 Sep 2003 09:15:06 -0500
Newsgroups: comp.lang.lisp
Message-ID: <>
Michael Sullivan <> wrote:
| But you essentially have that in the Common Lisp Standard.  Have you
| read it through?  It's clear that there is a core set of standards, and
| then there are a number of separate sets of capabilities that could
| mostly be built on top of that basic standard.  
| If someone really wanted to implement a non-ANSI, bare-common-lisp that
| behaved very much like common lisp, but left out a ton of functions and
| macros in the standard which did not require implementation support,
| they could certainly use much of the existing standard document as a
| specification.

Just as a reminder: One could even legitimately call it "a subset
of Common Lisp" if it met the extremely minimal requirement given
in CLHS "1.7 Language Subsets":

	For a language to be considered a subset, it must have the property
	that any valid program in that language has equivalent semantics
	and will run directly (with no extralingual pre-processing, and
	no special compatibility packages) in any conforming implementation
	of the full language.

I dare say that one could probably create a legitimate subset of Common
Lisp that was not much (if at all) bigger than an R5RS Scheme. This is
not intended as flame bait, but as a SWAG that one could write the spec
for such a thing in the same ~50 pages as the Scheme spec, even smaller
if one were permitted to refer to the ANSI Standard for things which
were exactly the same (e.g, the C[AD]*R functions come to mind) or the
same with some documented restrictions.

[Hmmm... Sounds like a candidate for a student semester project, eh?]

| Whether there is a market for such an implementation is another
| question...

Yes, er... well... indeed. That is actually the important question.

| ...but if there is, no one is stopping anyone from filling it right now.

Right. (See above.)


Rob Warnock, PP-ASEL-IA		<>
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