LISP
[from `LISt Processing language', but mythically from
`Lots of Irritating Superfluous Parentheses'] n. The name of 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. 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
crocks. When the
Right Thing has already
been done once, there is no justification for
bogosity in newer
languages.
