Newsgroups: comp.lang.scheme,comp.lang.lisp
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From: jeff@festival.ed.ac.uk (J W Dalton)
Subject: Re: Confused over Scheme Pedagogy of mutation procedures
References: <RICHTER.95Jul19084033@banach.math.purdue.edu> <pch-1907951304510001@m142.mystech.com> <3uk5qc$ol6@mozo.cc.purdue.edu>
Message-ID: <DCqsz1.n3z@festival.ed.ac.uk>
Organization: Edinburgh University
Date: Thu, 3 Aug 1995 16:11:25 GMT
Lines: 18
Xref: glinda.oz.cs.cmu.edu comp.lang.scheme:13413 comp.lang.lisp:18536

richter@banach.math.purdue.edu (Bill Richter) writes:

>1) I still contend that the environment/mutation model of SICP is
>really just lexical scoping as in C. 

Then let's see you write force and delay or stream/lazy lists
in C using the ordinary functions provided by C.

(You can of course write it *somehow* in C, as is shown by Scheme
interpreters written in C and by implementations of lexically-scoped
Lisps that compile to C.)

(And, of course, both C and Scheme are using lexical scoping.
C just doesn't provide it in full generality and doesn't have
local functions (e.g. the ones defined by letrec or written
as lambda-expressions in Scheme).

-- jeff
