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From: | felix winkelmann |
Subject: | Re: [Chicken-users] The predicate "atom?" considered bizarre |
Date: | Fri, 1 Sep 2006 08:59:34 +0200 |
On 8/31/06, John Cowan <address@hidden> wrote:
While messing around with some stuff in Paul Graham's paper "The Roots of Lisp" I was quite surprised to find that Chicken's "atom?" predicate returns #f on the empty list. This is the documented behavior. This is contrary to historic practice from Lisp 1.5 through Common Lisp. (Of course that is partly because () = NIL in that tradition, and NIL is a symbol.) R1RS was the last Scheme standard to specify ATOM, and it had the same semantics then. Why was this changed? Can it be fixed?
I have changes this. Note that "atom?" is now equivalent to "not-pair?". cheers, felix -- http://galinha.ucpel.tche.br:8081/blog/blog.ssp
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