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[[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 |last=Wexelblat |first=Richard L. |year=1978 |isbn=0127450408 |publisher=Association for Computing Machinery |page=173-183}}</ref> He was influenced by the design (and limitations) of the [[Fortran]] List Processing Language, which implemented the core idea of taking instruction input as a series of lists but used Fortran as a host language. McCarthy was dissatisfied with this language 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 published its design in a paper in ''[[Communications of the ACM]]'' in April 1960, entitled "Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I".<ref name="McCarthy">{{cite web |title=Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I |last=McCarthy |first=John |url=http://www-formal.stanford.edu/jmc/recursive.html |access-date=2006-10-13 |archive-url=https://web.archive.org/web/20131004215327/http://www-formal.stanford.edu/jmc/recursive.html |archive-date=2013-10-04}}</ref> He showed that with a few simple operators and a notation for anonymous functions borrowed from Church, one can build a [[Turing completeness|Turing-complete]] language for algorithms.▼
[[Information Processing Language]] was the first [[Artificial intelligence|AI]] language, from 1955 or 1956, and already included many of the concepts, such as list-processing and recursion, which came to be used in Lisp.
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Two [[assembly language macros]] for the [[IBM 704]] became the primitive operations for decomposing lists: [[car and cdr|car]] (''Contents of the Address part of Register'' number) and [[car and cdr|cdr]] (''Contents of the Decrement part of Register'' number),<ref name="PREHISTORY">{{cite web |title=LISP prehistory - Summer 1956 through Summer 1958 |last=McCarthy |first=John |url=http://www-formal.stanford.edu/jmc/history/lisp/node2.html |access-date=2010-03-14}}</ref> where "register" refers to [[Processor register|registers]] of the computer's [[central processing unit]] (CPU). Lisp dialects still use {{Lisp2|car}} and {{Lisp2|cdr}} ({{IPAc-en|k|ɑːr}} and {{IPAc-en|ˈ|k|ʊ|d|ər}}) for the operations that return the first item in a list and the rest of the list, respectively.
▲McCarthy published
The first complete Lisp compiler, written in Lisp, was implemented in 1962 by Tim Hart and Mike Levin at MIT, and could be compiled by simply having an existing LISP interpreter interpret the compiler code, producing [[machine code]] output able to be executed at a 40-fold improvement in speed over that of the interpreter.<ref name="Levin">{{cite web |title=AI Memo 39-The new compiler |last1=Hart |first1=Tim |last2=Levin |first2=Mike |url=ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-039.pdf |archive-url=https://web.archive.org/web/20201213195043/ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-039.pdf |archive-date=2020-12-13 |access-date=2019-03-18}}</ref> This compiler introduced the Lisp model of [[incremental compiler|incremental compilation]], in which compiled and interpreted functions can intermix freely. The language used in Hart and Levin's memo is much closer to modern Lisp style than McCarthy's earlier code.
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