Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!tut.cis.ohio-state.edu!cs.utexas.edu!rice!titan!dorai
From: dorai@titan.rice.edu (Dorai Sitaram)
Newsgroups: comp.lang.scheme
Subject: Re: Request for Comments: A new n-ary function construction
Message-ID: <3181@brazos.Rice.edu>
Date: 22 Nov 89 23:36:31 GMT
References: <891122-121343-4098@Xerox>
Sender: root@rice.edu
Reply-To: dorai@titan.rice.edu (Dorai Sitaram)
Organization: Rice University, Houston
Lines: 34

In article <891122-121343-4098@Xerox> Pavel.pa@XEROX.COM writes:
>I would like to avoid using ``rest lists'' in my Scheme code, especially at
>the lowest levels, for a number of reasons: they are usually difficult to
>optimize and I don't like the language-level preference for the list type
>over, for example, vectors.  To get around the problem, I thought of
>extending the syntax of lambda-lists to the following:
>
><lambda-list> ::= <id>						\kill?
>                | ( <id>* )
>                | ( <id>+ . <id> )				\kill?
>                | ( <id>* "arbitrary" <id> <id> )
>                | ( <id>* "arbitrary" <id> <id> . <id> )	\kill?
>[...]

I _love_ this idea! Probably the only merit of the existing "rest
list" situation is that it made me work real[ly] hard to try to
rewrite my code so that I avoided using them, sometimes getting in the
process better-looking and better code incidentally. But, of course,
there are always some places where one needs must use "varargs," and
though Ch*z Scheme's case-lambda [1] construct goes some way toward
avoiding the nasty list-fixation, your solution is more general with
probably little or no (?) loss in efficiency. Luckily, both strategies
can be combined to good use (restricting case-lambda arglists to
non-rest-lists of course). What's RRRS have to say to this?

--dorai

[1] Dybvig & Hieb, A Variable-Arity Procedural Interface, 1988 ACM
	Conf. on Lisp and Functional Programming.
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