Haskell /ˈhæskəl/ is a standardized, general-purpose purely functional programming language, with non-strict semantics and strong static typing. It is named after logician Haskell Curry. The latest standard of Haskell is Haskell 2010. As of February 2016, a group is working on the next version, Haskell 2014.

Haskell features a type system with type inference and lazy evaluation. Type classes first appeared in the Haskell programming language. Its main implementation is the Glasgow Haskell Compiler.

Haskell on Wikipedia