Haskell is a purely functional programming language with a strong static type system. Named after logician Haskell Curry, it emerged from academic research and has profoundly influenced programming language design.
Origins
In 1987, researchers at a functional programming conference decided to consolidate efforts on lazy functional languages. The resulting committee created Haskell, first released in 1990, as an open standard for purely functional programming research.
Key Features
Haskell introduced or popularized many concepts:
- Pure functions: No side effects by default
- Lazy evaluation: Expressions evaluated only when needed
- Type classes: Ad-hoc polymorphism
- Monads: Structure for handling effects and sequencing
- Algebraic data types: Powerful type definitions
- Type inference: Hindley-Milner type system
Influence on Other Languages
Haskell’s ideas spread widely:
- Monads: Adopted by Scala, Rust, and others
- Type classes: Inspired traits in Rust and Scala
- Option/Maybe types: Now in most modern languages
- LINQ: C#‘s query syntax influenced by Haskell
- Async/await: Related to do-notation
Practical Use
Though often seen as academic, Haskell is used in:
- Financial technology (Standard Chartered, Barclays)
- Compiler development (GHC itself, Elm, PureScript)
- Web frameworks (Yesod, Servant)
- Facebook’s spam filtering (Sigma)