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From: alderson@netcom.com (Richard M. Alderson III)
Subject: Re: [history question] Why was typed lambda calculus not used?
In-Reply-To: jch@triere.ens.fr's message of 7 Nov 1994 20:33:09 GMT
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References: <PP000547.94Nov5004912@bedlam.interramp.com> <hbakerCyww5K.F62@netcom.com>
	<39m2u5$b0s@nef.ens.fr>
Date: Wed, 9 Nov 1994 00:37:55 GMT
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In article <39m2u5$b0s@nef.ens.fr> jch@triere.ens.fr (Juliusz Chroboczek)
writes:

>In article <hbakerCyww5K.F62@netcom.com>,
>Henry G. Baker <hbaker@netcom.com> wrote:

>>McCarthy freely admits that he didn't really understand _any_ lambda
>>calculus when he invented the first Lisp.

>>So it is probable that he wasn't aware of the typed lambda calculus at
>>the time.

>That sounds right to me; the similarity between Lisp and \-calculus has
>probably been noticed after Lisp was created.  However, we might still ask
>ourselves why Lisp is so similar to type-free \-calculus, and not to typed
>\-calculus.

From McCarthy, "Recursive Functions of Symbolic Expressions and Their
Computation by Machine, Part I" (_Communcations of the ACM_ vol. 3 number 4,
April 1960, pp. 184-195):

	  e. {\it Functions and Forms}. It is usual in mathematics--
	outside of mathematical logic--to use the word ``function''
	imprecisely and to apply it to forms such as $y^2 + x$.
	Because we shall later compute with expressions for functions,
	we need a distinction between functions and forms and a
	notation for expressing this distinction.  This distinction
	and a notation for describing it, from which we deviate
	trivially, is given by Church [3].

Reference 3 is

	A. Church, {\it The Calculi of Lambda-Conversion} (Princeton
	  University Press, Princeton, N. J., 1941).

Earlier in the McCarthy paper, he states that the original idea for Lisp arose
in 1958.  I don't have Stoyan's book to check, but I think LAMBDA existed even
then.

Note that JMC's statement is that he did not *understand* lambda-calculus, not
that he was unfamiliar with any particular form thereof.  And given his back-
ground in recursion theory, I'd be more surprised if he *were* unfamiliar with
it than not.

Not proof of anything, of course...
-- 
Rich Alderson   You know the sort of thing that you can find in any dictionary
                of a strange language, and which so excites the amateur philo-
                logists, itching to derive one tongue from another that they
                know better: a word that is nearly the same in form and meaning
                as the corresponding word in English, or Latin, or Hebrew, or
                what not.
                                                --J. R. R. Tolkien,
alderson@netcom.com                               _The Notion Club Papers_
