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From: desj@brahms (David desJardins)
Newsgroups: comp.lang.lisp
Subject: Re: A small brush fire ...
Message-ID: <415@cartan.Berkeley.EDU>
Date: Sun, 23-Nov-86 21:47:48 EST
Article-I.D.: cartan.415
Posted: Sun Nov 23 21:47:48 1986
Date-Received: Mon, 24-Nov-86 21:02:26 EST
References: <8868@duke.duke.UUCP>
Sender: daemon@cartan.Berkeley.EDU
Reply-To: desj@brahms (David desJardins)
Organization: Math Dept. UC Berkeley
Lines: 19

In article <8868@duke.duke.UUCP> jds@duke.UUCP (Joseph D. Sloan) asks why
good code can require lexical rather than dynamic scoping.

(define (addn n)
   (lambda (x) (+ x n)))

(define 2+ (addn 2))
(define 3+ (addn 3))

(2+ 4)

gives 6 (lexical) or 7 (dynamic).

   In general, you need lexical scoping whenever you want bindings of actual
to formal parameters to exist beyond the scope of the current evaluation.

   -- David desJardins

P.S. Read Abelson and Sussman.