Editing Information Processing Language (section)

==History==
IPL was first utilized to demonstrate that the theorems in ''[[Principia Mathematica]]'' which were proven laboriously by hand, by [[Bertrand Russell]] and [[Alfred North Whitehead]], could in fact be [[automated theorem proving|proven by computation]].  According to Simon's autobiography ''Models of My Life'', this application was originally developed first by hand simulation, using his children as the computing elements, while writing on and holding up note cards as the registers which contained the state variables of the program.

IPL was used to implement several early [[artificial intelligence]] programs, also by the same authors: the [[Logic Theorist]] (1956), the [[General Problem Solver]] (1957), and their [[computer chess]] program [[NSS (chess program)|NSS]] (1958).

Several versions of IPL were created: IPL-I (never implemented), IPL-II (1957 for [[JOHNNIAC]]), IPL-III (existed briefly), IPL-IV, IPL-V (1958, for [[IBM 650]], [[IBM 704]], [[IBM 7090]], [[Philco model 212]], many others. Widely used). IPL-VI was a proposal for an IPL hardware.<ref>{{FOLDOC|Information+Processing+Language}}</ref>{{sfn|Shaw|Newell|Simon|Ellis|1958}}{{sfn|Sammet|1969|p=389}}

A co-processor “IPL-VC” for the CDC 3600 at Argonne National Libraries was developed which could run IPL-V commands.{{sfn|Hodges|1964}}{{sfn|Sammet|1969|p=393–394}} It was used to implement another checker-playing program.{{sfn|Cowell|Reed|1965}} This hardware implementation did not improve running times sufficiently to “compete favorably with a language more directly oriented to the structure of present-day machines”.{{sfn|Carson|Robinson|1966|p=5}}

IPL was soon displaced by [[Lisp (programming language)|Lisp]], which had much more powerful features, a simpler syntax, and the benefit of automatic [[garbage collection (computer science)|garbage collection]].