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␈↓ ↓H␈↓␈↓βS␈↓∧ Artificial Intelligence Laboratory, STANFORD UNIVERSITY, Stanford, California 94305
␈↓ ↓H␈↓∧Telephone 415 497-4430␈↓ 
⊃April 16, 1976




␈↓ ↓H␈↓Dr. Herbert Stoyan
␈↓ ↓H␈↓DDR 806 Dresden
␈↓ ↓H␈↓Togliattistr. 40
␈↓ ↓H␈↓East Germany

␈↓ ↓H␈↓Dear Dr. Stoyan:

␈↓ ↓H␈↓Here are some answers to your questions.

␈↓ ↓H␈↓1.  I don't remember what Newell and Simon called their language.

␈↓ ↓H␈↓2.␈α The␈αvery␈α≡rst␈αversion␈αof␈α
Fortran,␈αwhich␈αcame␈αout␈αin␈α1957␈α
I␈αthink,␈αhad␈αthe␈αfacility␈αfor␈α
de≡ning
␈↓ ↓H␈↓a␈α
function␈αby␈α
a␈α
single␈αformula;␈α
 i.e.␈α
 you␈αcould␈α
put␈α
at␈αthe␈α
beginning␈α
of␈αthe␈α
program␈α
a␈αstatement
␈↓ ↓H␈↓like␈αD(x,y)=SQRT(x**2␈α
+␈αy**2)␈α
and␈αthen␈α
use␈αthe␈α
function␈αD␈α
later␈αin␈α
the␈αprogram.␈α
 The␈αfacility␈α
for
␈↓ ↓H␈↓de≡ning␈α∪a␈α∪function␈α∪by␈α∪by␈α∪a␈α∪subroutine␈α∪came␈α∪with␈α∪Fortran␈α∪2.␈α∪ Part␈α∪of␈α∪the␈α∀motovation␈α∪for
␈↓ ↓H␈↓conditional expressions was to make the original Fortran function facility more powerful.

␈↓ ↓H␈↓3.␈α I␈αtelephoned␈αRoland␈αSilver␈αand␈αhe␈αtold␈αme␈αthat␈αhe␈αinvented␈αa␈αmethod␈αof␈αcompacting␈αgarbage
␈↓ ↓H␈↓collection␈α⊂some␈α⊃years␈α⊂later␈α⊃but␈α⊂that␈α⊃he␈α⊂thought␈α⊃that␈α⊂I␈α⊃invented␈α⊂the␈α⊃original␈α⊂form␈α⊃of␈α⊂garbage
␈↓ ↓H␈↓collection␈α↔and␈α_this␈α↔agrees␈α↔with␈α_my␈α↔memory.␈α↔ Probably␈α_Abrahams␈α↔confused␈α_Silver's␈α↔later
␈↓ ↓H␈↓implementation with the original form still used in most LISP systems.

␈↓ ↓H␈↓Under␈αseparate␈αcover␈αI␈αam␈α
sending␈αyou␈αcopies␈αof␈αpapers␈α
by␈αVuillemin,␈αCadiou␈αand␈αMorris.␈α
 Goto
␈↓ ↓H␈↓is␈α∞at␈α∞Tokyo␈α∞University␈α∞and␈α
you␈α∞should␈α∞write␈α∞to␈α∞him␈α
directly␈α∞at␈α∞the␈α∞Department␈α∞of␈α
Information
␈↓ ↓H␈↓Sciences.

␈↓ ↓H␈↓I␈αwill␈αsend␈αyou␈αan␈α
o≠cial␈αinvitation␈αas␈αsoon␈αas␈αit␈α
is␈αde≡nite,␈αbut␈αI␈αam␈α
not␈αsure␈αthat␈αthis␈αwill␈αbe␈α
by
␈↓ ↓H␈↓the end of 1976.


␈↓ ↓H␈↓Best regards,



␈↓ ↓H␈↓John McCarthy
␈↓ ↓H␈↓Director
␈↓ ↓H␈↓Professor of Computer Science