Joy (programming language)

Joy is a purely functional programming language designed by Manfred von Thun of La Trobe University in Melbourne, Australia, first appearing in 2001. Unlike most functional languages, Joy is built around function composition rather than lambda calculus, and it is stack based and concatenative in style, meaning every function takes a stack as its argument and returns a stack as its result, with concatenation of program text directly representing the composition of functions. Because functions in Joy have no formal parameters, programs written in it tend to be notably concise. The language drew inspiration from John Backus's FP language and its function level programming style, and its design independently converged on ideas found in Forth. Joy has in turn influenced later concatenative programming languages, including Factor, Cat, V and Trith.