Subject: Re: when type mismatch can be legal?
From: rpw3@rigden.engr.sgi.com (Rob Warnock)
Date: 1997/09/16
Newsgroups: comp.lang.lisp
Message-ID: <5vl1c4$1833a@fido.asd.sgi.com>

Barry Margolin  <barmar@bbnplanet.com> wrote:
+---------------
| (if (program-halts-p #'some-function)
|     (+ 'x 3)
|     (+ 'x 4))
| 
| You don't need to solve the halting problem to know that this form is
| undefined, so a compiler could refuse to compile this.
+---------------

Unless somebody did a (set! + my-whizzy-extended-plus) earlier...


-Rob

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