LISP n.
[from `LISt Processing language', but mythically from `Lots of Irritating Superfluous Parentheses'] AI's mother tongue, a language based on the ideas of (a) variable-length lists and trees as fundamental data types, and (b) the interpretation of code as data and vice-versa. Invented by John McCarthy at MIT in the late 1950s, it is actually older than any other [HLL] still in use except FORTRAN. Accordingly, it has undergone considerable adaptive radiation over the years; modern variants are quite different in detail from the original LISP 1.5. The dominant HLL among hackers until the early 1980s, LISP now shares the throne with [C]. Its partisans claim it is the only language that is truly beautiful. See [languages of choice].
All LISP functions and programs are expressions that return values; this, together with the high memory utilization of LISPs, 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".
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 [crock]s. When the [Right Thing] has already been done once, there is no justification for [bogosity] in newer languages.
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