Maude - Programming language

Maude is a programming language created in 1990.

#1170on PLDB

34Years Old

Maude is a high-level language and high-performance system supporting both equational and rewriting logic computation for a wide range of applications.

Maude first developed in Universidad de Navarra and Universidad de Málaga and Universidad Complutense and Centro Informático Científico de Andalucía and SRI International
Explore Maude snippets on Rosetta Code
Maude on HOPL
Read more about Maude on Semantic Scholar: 1.

Example from the web:

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 ! .