Wikipedia
Fudgets
In computing, Fudgets is a graphical user interface toolkit for the functional programming language Haskell and the X Window System. Fudgets makes it easy to create client–server applications that communicate via the Internet.
Most of the work on Fudgets was done in 1991-1996 by Thomas Hallgren and Magnus Carlsson.
The authors claim that many of the advantages of Fudgets come from the fact that they are programmed in a lazy functional programming language.
The main entity of toolkit is fudget (implemented on low level through stream processors) which has its own input and output. Fudgets can be composed in parallel or sequence yielding new fudget which can be used in code as any other fudget.