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From: shebs@utah-orion.UUCP (Stanley T. Shebs)
Newsgroups: comp.lang.lisp
Subject: Re: Circular Lists - (nf)
Message-ID: <152@utah-orion.UUCP>
Date: Sun, 15-Mar-87 13:53:44 EST
Article-I.D.: utah-ori.152
Posted: Sun Mar 15 13:53:44 1987
Date-Received: Mon, 16-Mar-87 03:57:13 EST
References: <2700001@uicsg.UUCP> <6900003@iaoobelix.UUCP> <5044@shemp.ucla-cs.UCLA.EDU>
Reply-To: shebs@utah-orion.UUCP (Stanley T. Shebs)
Organization: PASS Research Group
Lines: 17

In article <5044@shemp.ucla-cs.UCLA.EDU> flowers@CS.UCLA.EDU (Margot Flowers) writes:

>Infinite lists are more appriately embodied in streams (see
>Abelson&Sussman 3.4).

From a practical point of view, once the circular list is constructed, there
is no more consing, while all the stream implementations I've seen use storage
like there's no tomorrow.  I'd be really impressed by a compiler that could
transform a stream into a circular list if possible (don't some functional
language systems try to do that?).

BTW, it's never even occurred to me to use a circular list to model a stream.
Can anybody give a real example, along with enough context to demonstrate
that it was necessary and not a frob by a RPLACD fan?

							stan shebs
							shebs@cs.utah.edu