Haskell

Haskell /ˈhæskəl/^[3] is a purely functional programming language. It is named after Haskell Brooks Curry, a U.S. mathematician who contributed a lot to logic. Haskell is based on lambda calculus and uses the Greek letter lambda as its logo. The main implementations are the Glasgow Haskell Compiler (GHC), and Hugs, a Haskell interpreter.

Haskell

Paradigm	functional, lazy/non-strict, modular
Designed by	Simon Peyton Jones, Lennart Augustsson, Dave Barton, Brian Boutel, Warren Burton, Joseph Fasel, Kevin Hammond, Ralf Hinze, Paul Hudak, John Hughes, Thomas Johnsson, Mark Jones, John Launchbury, Erik Meijer, John Peterson, Alastair Reid, Colin Runciman, Philip Wadler
First appeared	1990; 35 years ago (1990)
Stable release	Haskell 2010[1] / July 2010; 14 years ago (2010-07)
Preview release	Announced as Haskell 2014[2]
Typing discipline	static, strong, inferred
OS	Cross-platform
Filename extensions	.hs, .lhs
Website	haskell.org
Major implementations
GHC, Hugs, NHC, JHC, Yhc, UHC
Dialects
Helium, Gofer

Examples

The following is an example Hello World program in Haskell:

module Main where

main :: IO ()
main = putStrLn "Hello, World!"

One way to create an infinite list of Fibonacci numbers is this:^[4]

fib n = fibs !! n
        where fibs = 0 : 1 : zipWith (+) fibs (tail fibs)

Influence

Haskell was influenced by many earlier programming languages. These were Clean, FP, Gofer, Hope and Hope⁺, Id, ISWIM, KRC, Lisp, Miranda, ML and Standard ML, Orwell, SASL, SISAL, and Scheme.^[5]

Haskell itself has influenced many later programming languages, such as Agda,^[6] Bluespec,^[7] C++11/Concepts,^[8] C#/LINQ,^{[9][10][11][12]} Cayenne,^[9] Clean,^[9] Clojure,^[13] CoffeeScript,^[14] Curry,^[9] F#,^[15] Isabelle,^[9] Java/Generics,^[9] Mercury,^[9] Perl 6,^[16] Python,^[9][17] Scala,^[9][18] Visual Basic 9.0.^[9][10]