Q
    Per Bothner (bothner@cygnus.com)

    A very high-level programming language written in C++.
    Where APL uses arrays to avoid explicit looping, Q uses
    generalized sequences (finite or infinite, stored or
    calculated on demand).  Q has lexical scoping, and some
    support for logical and constraint programming.  Q can
    be compiled (into C++), or interpreted interactively.
    Q contains a C++ hierarchical set of classes for representing 
    numbers (including infinite-precision rationals), functional
    closures, collections, files, symbols, and so on.  Uses GMP.
    There are also functions that implement Common Lisp and
    Scheme functionality.