Editing FP (programming language) (section)

{{Short description|Programming language}}
{{Infobox programming language
|name = FP
|logo =
|paradigm = [[Function-level programming|Function-level]]
|year = 1977
|designer = [[John Backus]]
|developer =
|latest release version =
|latest release date =
|typing =
|implementations =
|dialects = FP84
|influenced_by = [[APL (programming language)|APL]]<ref name="Hudak 1989">[https://dl.acm.org/doi/10.1145/72551.72554 The Conception, Evolution, and Application of Functional Programming Languages] {{Webarchive|url=https://web.archive.org/web/20160311204021/http://haskell.cs.yale.edu/wp-content/uploads/2011/01/cs.pdf |date=2016-03-11 }} Paul Hudak, 1989</ref>
|influenced = [[FL (programming language)|FL]], [[Haskell (programming language)|Haskell]], [[Joy (programming language)|Joy]]
}}

'''FP''' (short for ''functional programming'')<ref name="Backus 1977"/> is a [[programming language]] created by [[John Backus]] to support the [[function-level programming]]<ref name="Backus 1977"/> paradigm. It allows building programs from a set of generally useful primitives and avoiding named variables (a style also called [[tacit programming]] or "point free"). It was heavily influenced by [[APL (programming language)|APL]] developed by [[Kenneth E. Iverson]] in the early 1960s.<ref name=acm/>

The FP language was introduced in Backus's 1977 [[Turing Award]] paper, "Can Programming Be Liberated from the von Neumann Style?", subtitled "a functional style and its algebra of programs."  The paper sparked interest in functional programming research,<ref>{{cite web|last1=Yang|first1=Jean|title=Interview with Simon Peyton-Jones|url=https://www.cs.cmu.edu/~popl-interviews/peytonjones.html|website=People of Programming Languages|date=2017}}</ref> eventually leading to modern functional languages, which are largely founded on the [[lambda calculus]] paradigm, and not the function-level paradigm Backus had hoped. In his Turing award paper, Backus described how the FP style is different:

{{blockquote|An FP system is based on the use of a fixed set of combining forms called functional forms. These, plus simple definitions, are the only means of building new functions from existing ones; they use no variables or substitutions rules, and they become the operations of an associated algebra of programs. All the functions of an FP system are of one type: they map objects onto objects and always take a single argument.<ref name="Backus 1977"/>}}

FP itself never found much use outside of academia.<ref name="p21">{{cite web|last1=Hague|first1=James|title=Functional Programming Archaeology|url=http://prog21.dadgum.com/14.html|website=Programming in the Twenty-First Century|date=December 28, 2007}}</ref> In the 1980s Backus created a successor language, [[FL (programming language)|FL]] as an internal project at IBM Research.