Haskell is a standardized, general-purpose purely functional

Purely functional

Purely functional is a term in computing used to describe algorithms, data structures or programming languages that exclude destructive modifications...

 programming language

Programming language

A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....

, with non-strict semantics and strong static typing. It is named after logician Haskell Curry

Haskell Curry

Haskell Brooks Curry was an American mathematician and logician. Curry is best known for his work in combinatory logic; while the initial concept of combinatory logic was based on a single paper by Moses Schönfinkel, much of the development was done by Curry. Curry is also known for Curry's...

. In Haskell, "a function is a first-class citizen

First-class object

In programming language design, a first-class citizen , in the context of a particular programming language, is an entity that can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable...

" of the programming language. As a functional programming language, the primary control construct is the function

Subroutine

In computer science, a subroutine is a portion of code within a larger program that performs a specific task and is relatively independent of the remaining code....

. The language is rooted in the observations of Haskell Curry and his intellectual descendants, that "a proof is a program; the formula it proves is a type for the program".
Following the release of Miranda by Research Software Ltd, in 1985, interest in lazy functional languages

Lazy evaluation

In programming language theory, lazy evaluation or call-by-need is an evaluation strategy which delays the evaluation of an expression until the value of this is actually required and which also avoids repeated evaluations...

 grew: by 1987, more than a dozen non-strict, purely functional programming languages existed.