Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!apollo!mrst!sdti!turner
From: turner@sdti.SDTI.COM (Prescott K. Turner)
Newsgroups: comp.lang.misc
Subject: Re: first class functions (opps)
Summary: false advertising
Message-ID: <451@sdti.SDTI.COM>
Date: 5 May 89 16:17:00 GMT
References: <10253@orstcs.CS.ORST.EDU> <2400023@otter.hpl.hp.com>
Reply-To: turner@sdti.UUCP (0006-Prescott K. Turner, Jr.)
Organization: Software Development Technologies, Sudbury MA
Lines: 19

In article <2400023@otter.hpl.hp.com> kers@otter.hpl.hp.com (Chris Dollin) writes:
>Ones that do have proper first-class functions include Scheme, Common
>Lisp, ML (and any pure functional language worth mentioning), and Pop11.
>If you're interested, I can describe how Pop11 does its first-class
>functions; I won't burden the whole Net unless I get overwhelmed by
>requests.

I'm somewhat familiar with Scheme's "first-class" functions, and like them.
But isn't it false advertising to claim first-class functions unless you
can compare functions for equality just like other types?  This means that
the implementation will return "not-equal" if the functions are different,
return "equal" if they can be proved equivalent, and otherwise continue
searching for a proof or counterexample indefinitely.  Are there any
languages which support this?
--
Prescott K. Turner, Jr.
Software Development Technologies, Inc.
P.O. Box 366, Sudbury, MA 01776 USA         (508) 443-5779
UUCP: ...{harvard,mit-eddie}!sdti!turner    Internet: turner@sdti.sdti.com