NPL is a programming language created in 1977.

NPL is a functional programming language with pattern matching designed by Rod Burstall and John Darlington in 1977. The language allows certain sets and logic constructs to appear on the right hand side of definitions, e.g. setofeven(X) <= <:x: x in X & even(x) :>The NPL interpreter evaluates the list of generators from left to right so conditions can mention any bound variables that occur to their left. Read more on Wikipedia...

• NPL Wikipedia page
• NPL first developed in University of Edinburgh and Imperial College London