A combinator library is a software library which implements combinators

Combinatory logic

Combinatory logic is a notation introduced by Moses Schönfinkel and Haskell Curry to eliminate the need for variables in mathematical logic. It has more recently been used in computer science as a theoretical model of computation and also as a basis for the design of functional programming...

 for a functional programming language; "the key idea is this: a combinator library offers functions (the combinators) that combine functions together to make bigger functions". These kinds of libraries are particularly useful for allowing domain-specific programming language

Domain-specific programming language

In software development and domain engineering, a domain-specific language is a programming language or specification language dedicated to a particular problem domain, a particular problem representation technique, and/or a particular solution technique...

s to be easily embedded into a general purpose language by defining a few primitive functions for the given domain and turning over the task of expanding higher-level constructs to the general language. An example would be the monadic

Monads in functional programming

In functional programming, a monad is a programming structure that represents computations. Monads are a kind of abstract data type constructor that encapsulate program logic instead of data in the domain model...

 Parsec parser http://www.haskell.org/haskellwiki/Parsec for Haskell

Haskell (programming language)

Haskell is a standardized, general-purpose purely functional programming language, with non-strict semantics and strong static typing. It is named after logician Haskell Curry. In Haskell, "a function is a first-class citizen" of the programming language. As a functional programming language, the...

. The library approach allows the parsers to be first-class

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...

citizens of the language.

External links

• "Designing and Using Combinators: The Essence of Functional Programming"