SLIP is a list processing

computer programming language A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually def ...

, invented by

Joseph Weizenbaum Joseph Weizenbaum (8 January 1923 – 5 March 2008) was a German-American computer scientist and a professor at Massachusetts Institute of Technology, MIT. He is the namesake of the Weizenbaum Award and the Weizenbaum Institute. Life and career ...

in the 1960s. The name ''SLIP'' stands for Symmetric LIst Processor. It was first implemented as an extension to the Fortran programming language, and later embedded into MAD and

ALGOL ALGOL (; short for "Algorithmic Language") is a family of imperative computer programming languages originally developed in 1958. ALGOL heavily influenced many other languages and was the standard method for algorithm description used by the ...

.Computer Programming Languages – S
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ELIZA ELIZA is an early natural language processing computer program developed from 1964 to 1967 at MIT by Joseph Weizenbaum. Created to explore communication between humans and machines, ELIZA simulated conversation by using a pattern matching and ...

, an early

natural language processing Natural language processing (NLP) is a subfield of computer science and especially artificial intelligence. It is primarily concerned with providing computers with the ability to process data encoded in natural language and is thus closely related ...

computer program A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. It is one component of software, which also includes software documentation, documentation and other intangibl ...

created by Weizenbaum at the

MIT Artificial Intelligence Laboratory Computer Science and Artificial Intelligence Laboratory (CSAIL) is a research institute at the Massachusetts Institute of Technology (MIT) formed by the 2003 merger of the Laboratory for Computer Science (LCS) and the Artificial Intelligence L ...

General overview

In a nutshell, SLIP consisted of a set of FORTRAN "accessor" functions which operated on circular doubly linked lists with fixed-size data fields. The "accessor" functions had direct and indirect addressing variants.

List representation

The list representation had four types of cell: a ''reader'', a ''header'', a ''sublist indicator'', and a ''payload'' cell. The header included a reference count field for

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purposes. The sublist indicator allowed it to be able to represent nested lists, such as (A, B, C, (1, 2, 3), D, E, F) where (1, 2, 3) is a sublist indicated by a cell in the '*' position in the list (A, B, C, *, D, E, F). The reader was essentially a state history stack—a good example of a memento pattern—where each cell pointed to the header of the list being read, the current position within the list being read, and the level or depth of the history stack.

References

*
Symmetric List Processor
', Joseph Weizenbaum, CACM 6:524-544(1963). Sammet 1969, p. 387. * '' Computer Power and Human Reason: From Judgment To Calculation'', Joseph Weizenbaum, San Francisco: W. H. Freeman, 1976 Fortran libraries Programming languages {{compu-lang-stub