Q is a powerful and extensible functional programming language based on the
term rewriting calculus. You specify an arbitrary system of equations which
the interpreter uses as rewrite rules to reduce expressions to normal form. Q
is useful for scientific programming and other advanced applications, and also
as a sophisticated kind of desktop calculator. The distribution includes the Q
programming tools, the standard library, add-on modules for interfacing to GNU
dbm, GNU Octave, GGI, ImageMagick, Tcl/Tk and IBM's Data Explorer, and
an Emacs mode.

WWW: http://q-lang.sourceforge.net/