OWHY :- or what have you
JArchibald at aol.com
JArchibald at aol.com
Thu Jun 1 11:33:48 UTC 2000
For your morning entertainment--
Concerning OWHY, the first on-the-fly-acronym (which we will neologize as
OTFA, a FLA), the great-grandfather to 'IMHO', 'FWIW', OWHY (self application
before definition here. See below).
"A Type-Theoretic Alternative to CUCH, ISWIM, and OWHY*"
Dana Scott
This is one of Dana Scott's most famous unpublished (but widely distributed
{it had on the cover page: "Dana Scott no longer subscribes to the ideas in
this paper. DO NOT REDISTRIBUTE" in bold print} -- if you ever want to get a
massive distribution of difficult material, use this on your paper). He had
quite a number of unpublished papers making the rounds as Xerox copies, as I
recall. A post-Doc (whose name evades me at the moment) from Penn State
visiting for the summer at IBM Research had dutifully collected the whole
bunch. What I saw and what I copied shall remain unmentioned (to protect the
anonymity of the guilty).
The paper is essentially typed Combinatory Logic. As I recall, Dana tried to
dip his toe into typing here, but didn't go the whole way. John Reynolds
once told me, "If you're going to type, you're going to have to type
everything." Smalltalk does it beautifully [typing everything] (for what some
aboriginal programmers refer to as a "type-less" language) in a
semi-functional format.
This is not a good paper from which to learn Combinatory Logic. Nor is 'Curry
and Feys' for that matter. If you are interested (and you like 'macro
processor'-like thinking), the resource to get your hands on is the book:
"Introduction to Combinators ..." by Hindley, et al., unfortunately out of
print. A good exercise is to build a Combinatory Logic evaluator in your
favorite (owhy) programming language. Wilhelm van der Pol (Netherlands Algol
68 expert) did precisely this during a sabbatical at IBM Research; I looked
over his shoulder.
CUCH is Curry-Church. It had been used in the title of a paper (by ?). I
think it actually was made into a programming language at one point. I've
never seen it, but as I remember it was just a demonstrator for automated
Combinatory Logic (untyped).
ISWIM was Landin's language from "The next 700 Programming Languages." It was
the genesis of functional programming as it divorced itself from LISP. I
don't think Landin ever implemented ISWIM, but I might be mistaken here. Bill
Burge wrote an excellent book (the thing to read after "The Next 700
Programming Languages") on functional programming which is 100% ISWIM, and is
an excellent read on Combinatory Logic Programming (untyped). Both he and
Burt Leavenworth (both members of the programming language lunch table gang
at IBM Research) had built local (to IBM) implementations of ISWIM.
*or what have you.
Cheers,
Jerry.
____________________________
Jerry L. Archibald
systemObjectivesIncorporated
____________________________
"I can't think of the author." Anon.
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