Lisp (programming language): Difference between revisions

Revision as of 09:36, 27 May 2025

Revision as of 12:34, 6 June 2025

Line 99:

{{Multiple image |direction=vertical |image1=John McCarthy Stanford.jpg |image2=Steve Russell.jpg |footer=[[John McCarthy (computer scientist)|John McCarthy]] (top) and [[Steve Russell (computer scientist)|Steve Russell]]}}

[[John McCarthy (computer scientist)|John McCarthy]] began developing Lisp in 1958 while he was at the [[Massachusetts Institute of Technology]] (MIT). He was motivated by a desire to create an AI programming language that would work on the [[IBM 704]], as he believed that "IBM looked like a good bet to pursue Artificial Intelligence research vigorously."<ref name="wexelblat-history-programming-languages">{{cite book |title=History of programming languages |last1=McCarthy |first1=John |last2=Wexelblat |first2=Richard L. |year=1978 |isbn=0127450408 |publisher=Association for Computing Machinery |pages=173–183}}</ref> He was inspired by [[Information Processing Language]], which was also based on list processing, but did not use it because it was designed for different hardware and he found an algebraic language more appealing.<ref name="wexelblat-history-programming-languages" /> Due to these factors, he consulted on the design of the [[Fortran]] List Processing Language, which was implemented as a Fortran library. However, he was dissatisfied with it because it did not support [[Recursion (computer science)|recursion]] or a modern [[Conditional (computer programming)#If–then(–else)|if-then-else]] statement (which was a new concept when lisp was first introduced) {{NoteTag|At the time, Fortran had an if-then-else construct that accepted line numbers as jump targets, in the manner of a [[Goto]] statement, rather than accepting arbitrary expression in "then" and "else" blocks}}.<ref name="wexelblat-history-programming-languages" />

McCarthy's original notation used bracketed "[[M-expression]]s" that would be translated into [[S-expression]]s. As an example, the M-expression {{Lisp2|car[cons[A,B]]}} is equivalent to the S-expression {{Lisp2|(car (cons A B))}}. Once Lisp was implemented, programmers rapidly chose to use S-expressions, and M-expressions were abandoned.<ref name="wexelblat-history-programming-languages"/> M-expressions surfaced again with short-lived attempts of [[MLisp]]<ref name="Smith">{{cite book |last=Smith |first=David Canfield |title=MLISP Users Manual |url=http://www.softwarepreservation.org/projects/LISP/stanford/Smith-MLISP-AIM-84.pdf |access-date=2006-10-13}}</ref> by Horace Enea and [[CGOL]] by [[Vaughan Pratt]].