SET Language: mathematical programming language closely resembling the language of sets and functions used by Mathematicians. Lets users define sets, then define functions and binary operations on the sets: reference documentation for the library of b...
SET Language 2, close relative of SETL, has some clumsy support for closures, an experimental (broken) object system, and redefines integer division to mean something different than in SETL: 3/2 yields 1.5 in SETL, but only 1 in SETL2.