Path: utzoo!dciem!array!colin
From: colin@array.UUCP (Colin Plumb)
Newsgroups: comp.lang.scheme
Subject: Re: terminology question
Message-ID: <583@array.UUCP>
Date: 23 Aug 90 19:17:45 GMT
References: <1466@tub.UUCP> <418@ministry.cambridge.apple.com> <JINX.90Aug22120120@chamarti.ai.mit.edu>
Organization: Array Systems Computing, Inc., Toronto, Ontario, CANADA
Lines: 17

In article <JINX.90Aug22120120@chamarti.ai.mit.edu> jinx@zurich.ai.mit.edu writes:
> I like to think of Scheme reified continuations as re-entrant.

This property does some interesting things to functionality.
Obviously,
(define (foo) (1))
Is strictly functional - it can be replaced by "1" wherever it appears.
Less obviously,
(define (bar x) (cons x 1))
is not a function, since it can be called like:
(let ((y (call/cc bar)))
     (if (= (cadr y) 1) ((car y) (cons (car y) 2)))
     (cadr y))
And it will have returned (<continuation> 2).  I find this behaviour
disturbing in some odd way.
-- 
	-Colin