History
The concept of monad programming appeared already in the 1980s in the programming language Opal even though it was called "commands" and never formally specified. Eugenio Moggi first described the general use of monads to structure programs in 1991. Several people built on his work, including programming language researchers Philip Wadler and Simon Peyton Jones (both of whom were involved in the specification of Haskell). Early versions of Haskell used a problematic "lazy list" model for I/O, and Haskell 1.3 introduced monads as a more flexible way to combine I/O with lazy evaluation.
In addition to I/O, scientific articles and Haskell libraries have successfully applied monads to topics including parsers and programming language interpreters. The concept of monads along with the Haskell do-notation for them has also been generalized to form arrows.
Haskell and its derivatives have been for a long time the only major users of monads in programming. There also exist formulations in Scheme, Perl, Racket, Clojure and Scala, and monads have been an option in the design of a new ML standard. Recently F# has included a feature called computation expressions or workflows, which are an attempt to introduce monadic constructs within a syntax more palatable to programmers with an imperative background.
Effect systems are an alternative way of describing side effects as types.
Read more about this topic: Monad (functional Programming)
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