Haskell

A purely functional language where functions are mathematics: no side effects, values immutable, effects explicit in types.

Core Principles & Analysis

• A committee designed it in 1987 to unify the proliferating lazy functional languages.
• It is named for the logician Haskell Curry, whose combinators underlie its function theory.
• Its type system inspired the option, result and async patterns now common in industry languages.