Editing Prolog (section)

{{Short description|Programming language that uses first order logic}}
{{About|the programming language|the narrative device|Prologue|other uses|Prologue (disambiguation)}}
{{Infobox programming language
| paradigm = [[Logic programming|Logic]]
| designers = [[Alain Colmerauer]]
| released = {{Start date and age|1972}}
| latest release version = Part 1: General core-Edition 1 ({{Start date and age|1995|06}})<br />Part 2: Modules-Edition 1 ({{Start date and age|2000|06}})
| latest release date =
| typing = Untyped (its single data type is "term")
| implementations = [http://www.amzi.com/#apls Amzi! Prolog], [[B-Prolog]], [[Ciao (programming language)|Ciao]], [[ECLiPSe]], [[GNU Prolog]],  [[Logic Programming Associates|LPA Prolog]], [[Poplog]], [https://homepages.inf.ed.ac.uk/stg/research/Psharp/ P#], [[Quintus Prolog]], [https://www.scryer.pl/ Scryer Prolog], [https://sicstus.sics.se/ SICStus], [https://dobrev.com/ Strawberry], [[SWI-Prolog]],  [http://tau-prolog.org/ Tau Prolog], [http://tuprolog.unibo.it/ tuProlog], [https://www.lpai.uk/win.htm WIN-PROLOG] [[XSB]], [[YAP (Prolog)|YAP]].
| dialects = [[#ISO Prolog|ISO Prolog]], Edinburgh Prolog
| influenced by = [[Planner (programming language)|Planner]]
| influenced = [[Constraint Handling Rules|CHR]], [[Clojure]], [[Datalog]], [[Erlang (programming language)|Erlang]], [http://epilog.stanford.edu/ Epilog], [[KL0]], [[KL1]], [[Logtalk]], [[Mercury (programming language)|Mercury]], [[Oz (programming language)|Oz]], [[Strand (programming language)|Strand]], [[Visual Prolog]]
| file_ext = <code>.pl</code>, <code>.pro</code>, <code>.P</code>
| website = Part 1: {{URL|https://www.iso.org/standard/21413.html}}<br /> Part 2: {{URL|https://www.iso.org/standard/20775.html}}
| wikibooks = Prolog
}}

'''Prolog''' is a [[logic programming]] language that has its origins in [[artificial intelligence]], [[automated theorem proving]] and [[computational linguistics]].<ref name=Clocksin2003>{{Cite book |last1=Clocksin |first1=William F. |last2=Mellish |first2=Christopher S. |title=Programming in Prolog |year=2003 |publisher=Springer-Verlag |location=Berlin; New York |isbn=978-3-540-00678-7}}</ref><ref name=Bratko2012>{{Cite book |last1=Bratko |first1=Ivan |title=Prolog programming for artificial intelligence |edition=4th |year=2012 |publisher=Addison Wesley |location=Harlow, England; New York |isbn=978-0-321-41746-6}}</ref><ref name=Covington1994>{{Cite book |last1=Covington |first1=Michael A. |title=Natural language processing for Prolog programmers |year=1994 |publisher=Prentice Hall |location=Englewood Cliffs, N.J. |isbn=978-0-13-629213-5}}</ref>

Prolog has its roots in [[first-order logic]], a [[formal logic]], and unlike many other [[programming language]]s, Prolog is intended primarily as a [[declarative programming]] language: the program is a set of facts and [[Horn clause|rules]], which define [[Finitary relation|relations]].  A [[computation]] is initiated by running a ''query'' over the program.<ref name=lloyd84/>

Prolog was one of the first logic programming languages<ref>See {{section link|Logic programming|History}}.</ref> and remains the most popular such language today, with several free and commercial implementations available. The language has been used for [[automated theorem proving|theorem proving]],<ref>{{Cite journal |last1=Stickel |first1=M. E. |title=A prolog technology theorem prover: Implementation by an extended prolog compiler |journal=[[Journal of Automated Reasoning]] |volume=4 |issue=4 |pages=353–380 |year=1988 |doi=10.1007/BF00297245 |citeseerx=10.1.1.47.3057 |s2cid=14621218}}</ref> [[expert system]]s,<ref>{{cite book |author=Merritt, Dennis |title=Building expert systems in Prolog |publisher=Springer-Verlag |location=Berlin |year=1989 |isbn=978-0-387-97016-5 |url-access=registration |url=https://archive.org/details/buildingexpertsy0000merr}}</ref> [[term rewriting]],<ref>Felty, Amy. "A logic programming approach to implementing higher-order term rewriting." Extensions of Logic Programming (1992): 135-161.</ref> [[type system]]s,<ref name="Lee2015">{{cite book|author=Kent D. Lee|title=Foundations of Programming Languages|url=https://books.google.com/books?id=dERFBgAAQBAJ&q=prolog+type+inference&pg=PA298|date=19 January 2015|publisher=Springer|isbn=978-3-319-13314-0|pages=298–}}</ref> and [[automated planning]],<ref name="Schmid2003">{{cite book|author=Ute Schmid|author-link= Ute Schmid |title=Inductive Synthesis of Functional Programs: Universal Planning, Folding of Finite Programs, and Schema Abstraction by Analogical Reasoning|url=https://books.google.com/books?id=p-Fy25LE4lMC|date=21 August 2003|publisher=Springer Science & Business Media|isbn=978-3-540-40174-2}}</ref> as well as its original intended field of use, [[natural language processing]].<ref>{{cite book |author1=Fernando C. N. Pereira |author-link1=Fernando Pereira |author2=Stuart M. Shieber |year=2005 |title=Prolog and Natural Language Analysis |publisher=Microtome |url=http://mtome.com/Publications/PNLA/pnla.html}}</ref><ref name=lally>{{cite web |author1=Adam Lally |author2=Paul Fodor |date=31 March 2011 |url=http://www.cs.nmsu.edu/ALP/2011/03/natural-language-processing-with-prolog-in-the-ibm-watson-system/ |title=Natural Language Processing With Prolog in the IBM Watson System |publisher=Association for Logic Programming |access-date=13 June 2014 |archive-date=3 September 2014 |archive-url=https://web.archive.org/web/20140903064037/http://www.cs.nmsu.edu/ALP/2011/03/natural-language-processing-with-prolog-in-the-ibm-watson-system/ |url-status=dead }} See also [[Watson (computer)]].</ref>

Prolog is a Turing-complete, general-purpose programming language, which is well-suited for intelligent knowledge-processing applications.