Lisp

language LISt Processing language.

(Or mythically "Lots of Irritating Superfluous Parentheses").

Artificial Intelligence's mother tongue, a symbolic,

functional, recursive language based on the ideas of

lambda-calculus, variable-length lists and trees as

fundamental data types and the interpretation of code as data

and vice-versa.

Data objects in Lisp are lists and atoms. Lists may contain

lists and atoms. Atoms are either numbers or symbols.

Programs in Lisp are themselves lists of symbols which can be

treated as data. Most implementations of Lisp allow functions

with side-effects but there is a core of Lisp which is

purely functional.

All Lisp functions and programs are expressions that return

values; this, together with the high memory use of Lisp, gave

rise to Alan Perlis's famous quip (itself a take on an Oscar

Wilde quote) that "Lisp programmers know the value of

everything and the cost of nothing".

The original version was LISP 1, invented by John McCarthy

[email protected] at MIT in the late 1950s. Lisp is

actually older than any other high level language still in

use except Fortran. Accordingly, it has undergone

considerable change over the years. Modern variants are quite

different in detail. The dominant HLL among hackers until

the early 1980s, Lisp now shares the throne with C. See

languages of choice.

One significant application for Lisp has been as a proof by

example that most newer languages, such as COBOL and Ada,

are full of unnecessary crocks. When the Right Thing has

already been done once, there is no justification for

bogosity in newer languages.

See also Association of Lisp Users, Common Lisp, FranzLisp, MacLisp, Portable Standard Lisp, Interlisp,

Scheme, ELisp, Kamin's interpreters.

[Jargon File]

(1995-04-16)