Information Processing Language (IPL) was a programming language developed by Allen Newell, Cliff Shaw and Herbert Simon at RAND Corporation and the Carnegie Institute of Technology from about 1956. It included features intended to support programs that could perform general problem solving, including lists, associations, schemas (frames), dynamic memory allocation, data types, recursion, associative retrieval, functions as arguments, and generators (streams).
IPL was used to implement two of the first artificial intelligence programs, by the same authors: the Logic Theory Machine (1956) and the General Problem Solver (1957), and also their 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, many others. Widely used), IPL-VI.
However the language was soon displaced by Lisp, which had similar features but a simpler syntax and the benefit of automatic garbage collection.
References
- Allen Newell, Herbert A. Simon, Biographical Memoirs, National Academy of Sciences - includes a short section on IPL.
- Information Processing Language, FOLDOC