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by values of parameterized data types. Modifiable computations are modeled by allowing a pure function to be applied to values of the "inner" type, thus creating the new overall value which represents the modified computation (which might yet to be run).
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This article is about the design pattern for mapping functions over a generic type. For the term "functor" as used in C++, see
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Chapter 11 Functors, Applicative
Functors and Monoids in Learn You a Haskell for Great Good!
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to a binary tree of integers increments each integer in the tree by one.
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Haskell, lists are a simple example of a functor. We may implement
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This declaration says that any type of
Functor must support a method
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Functors form a base for more complex abstractions like
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A binary tree may similarly be described as a functor:
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291:Applicative Functor
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1265:Jim Coplien
1240:Grady Booch
1225:Erich Gamma
1169:Type tunnel
1154:Object pool
1149:Null object
1144:Mock object
1006:Interceptor
976:Thread pool
891:Concurrency
837:Interpreter
644:12 December
613:HaskellWiki
548:will apply
210:stands for
1332:Categories
1179:Delegation
1114:Blackboard
819:Behavioral
771:Structural
733:Creational
634:"Functors"
594:References
68:type class
1245:Kent Beck
971:Semaphore
961:Scheduler
804:Flyweight
794:Decorator
789:Composite
761:Singleton
756:Prototype
546:fmap f tr
32:fmap (+1)
30:Applying
1305:See also
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847:Mediator
842:Iterator
724:patterns
576:See also
435:instance
310:Examples
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1159:Servant
1091:Model 2
951:Reactor
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877:Visitor
852:Memento
832:Command
779:Adapter
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618:17 June
438:Functor
299:Comonad
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297:, and
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272:=>
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219:Scala
117:->
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84:where
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1164:Twin
1021:MVVM
936:Lock
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