Path: ...!feeds.phibee-telecom.net!2.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Julieta Shem <jshem@yaxenu.org>
Newsgroups: comp.lang.lisp
Subject: Re: Church numerals in early lisp implementations?
Date: Sun, 12 May 2024 16:55:46 -0300
Organization: A noiseless patient Spider
Lines: 24
Message-ID: <877cfykdod.fsf@yaxenu.org>
References: <875xvkmta1.fsf@yaxenu.org>
	<86frun24at.fsf@williamsburg.bawden.org>
MIME-Version: 1.0
Content-Type: text/plain
Injection-Date: Sun, 12 May 2024 21:55:47 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="8e50673e87fb0a0d3fd03bcc70b8d225";
	logging-data="3116687"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1+QCJKiTjoxUof/DWIEJezD5iV6xXb+36A="
Cancel-Lock: sha1:imkWqTbuzZHyA3rWm6V890PW8Qg=
	sha1:OSWiNsRUd8ep9ZEGAa0psr7vU/0=
Bytes: 1994

Alan Bawden <alan@csail.mit.edu> writes:

> Julieta Shem <jshem@yaxenu.org> writes:
>
>    McCarthy wrote this in ``History of Lisp''.
>
>    > Numbers were originally implemented in LISP I as lists of atoms, and
>    > this proved too slow for all but the simplest computations.
>
>    Was that Church numerals?
>
> Certainly not.
>
> The "atoms" is question were probably machine words containing the
> digits of the number in some suitable base.  I would guess base 2^36 or
> 2^35, depending on how they chose to represent negative numbers --
> similar to the way GMP still works today.  But I don't know for sure.
> I've never seen this documented anywhere.

Do you know if they have big numbers in those early implementations?
(Why would they use a list of things?)  I'm now thinking that by ``list
of atoms'' (and with the light of from your post) they were supporting
big numbers.  Their algorithms were perhaps naive, explaining ``the too
slow for all but the simplest computations''.  Thanks!