Subject: Re: I'm stuck: composition of functions
From: rpw3@rigden.engr.sgi.com (Rob Warnock)
Date: 1996/11/03
Newsgroups: comp.lang.scheme
Message-ID: <55gq93$aeq@tokyo.engr.sgi.com>

J.J.A. Koot <koot@sara.nl> wrote:
+---------------
| As far as I know: (if '() 'a 'b) ==> b
+---------------

IEEE Scheme requires (if '() 'a 'b) ==> a

But in R4RS it says, "It is no longer specified whether the empty list
counts as true of false in conditional expressions." (But they then
implicitly [to my reading] encourage "true" by reminding the reader
about IEEE Scheme.)

In any case, implementations do vary, so using "null?" is always the
safest thing.


-Rob

-----
Rob Warnock, 7L-551		rpw3@sgi.com
Silicon Graphics, Inc.		http://reality.sgi.com/rpw3/
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