Maude is a programming language created in 1990.
|#1169on PLDB||33Years Old|
Maude is a high-level language and high-performance system supporting both equational and rewriting logic computation for a wide range of applications.
fmod FACTORIAL is protecting INT . op undefined : -> Int . op _! : Int -> Int . var n : Int . eq 0 ! = 1 . eq n ! = if n < 0 then undefined else n * (sd(n, 1) !) fi . endfm red 11 ! .