First-class function: Difference between revisions

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In [[computer science]], a '''first class function''' is a [[programming language]] construct that allows [[function (programming)|function]] thatobjects canto be manipulatedtreated asin many respects like ordinary data objects. AIn particular, a first class function can be created during the execution of a program, stored in a data structure, modified using the data processing facilities of the [[programming language]], and passed as an argument to another function., and, [[Lispin some programming language|Lisp]]languages, andmodified [[Schemeusing programmingthe language|Scheme]]data areprocessing examplesfacilities of [[programmingthe language]]s that implement first class functions as [[primitive types|primitive datatypes]].

Support for first class functions is widely considered to be a required feature for [[functional programming language]]s. [[Lisp programming language|Lisp]], [[Scheme programming language|Scheme]], [[ML programming language|ML]], and [[Haskell programming language|Haskell]] are examples of functional programming languages that support first class functions.

Most modern programming languages support functions defined statically at compile time. [[C programming language|C]] additionally supports function pointers, which can be stored in data structures and passed as arguments to other functions. Nevertheless, C is not considered to support first class functions, since in general functions cannot be created dynamically during the execution of a program. The closest analog in C is that of a dynamically compiled function created by a [[just-in-time compiler]], which is compiled as an array of [[machine language]] instructions in memory and then cast to a function pointer. However, this technique is specific to the underlying hardware architecture and is therefore neither general nor portable.

==See also==

* [[closure (computer science)|closure]]

* [[function object]]

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