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class="vector-toc-link" href="#Execution"> <div class="vector-toc-text"> 1.5 Execution </div> </a> <ul id="toc-Execution-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Negation" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Negation"> <div class="vector-toc-text"> 1.6 Negation </div> </a> <ul id="toc-Negation-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Programming_in_Prolog" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Programming_in_Prolog"> <div class="vector-toc-text"> 2 Programming in Prolog </div> </a> <button aria-controls="toc-Programming_in_Prolog-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Programming in Prolog subsection </button> <ul id="toc-Programming_in_Prolog-sublist" class="vector-toc-list"> <li id="toc-Hello_World" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Hello_World"> <div class="vector-toc-text"> 2.1 Hello World </div> </a> <ul id="toc-Hello_World-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Compiler_optimization" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Compiler_optimization"> <div class="vector-toc-text"> 2.2 Compiler optimization </div> </a> <ul id="toc-Compiler_optimization-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Quicksort" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Quicksort"> <div class="vector-toc-text"> 2.3 Quicksort </div> </a> <ul id="toc-Quicksort-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Design_patterns_of_Prolog" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Design_patterns_of_Prolog"> <div class="vector-toc-text"> 3 Design patterns of Prolog </div> </a> <ul id="toc-Design_patterns_of_Prolog-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Higher-order_programming" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Higher-order_programming"> <div class="vector-toc-text"> 4 Higher-order programming </div> </a> <ul id="toc-Higher-order_programming-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Modules" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Modules"> <div class="vector-toc-text"> 5 Modules </div> </a> <ul id="toc-Modules-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Parsing" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Parsing"> <div class="vector-toc-text"> 6 Parsing </div> </a> <ul id="toc-Parsing-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Meta-interpreters_and_reflection" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Meta-interpreters_and_reflection"> <div class="vector-toc-text"> 7 Meta-interpreters and reflection </div> </a> <ul id="toc-Meta-interpreters_and_reflection-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Turing_completeness" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Turing_completeness"> <div class="vector-toc-text"> 8 Turing completeness </div> </a> <ul id="toc-Turing_completeness-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Implementation" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Implementation"> <div class="vector-toc-text"> 9 Implementation </div> </a> <button aria-controls="toc-Implementation-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Implementation subsection </button> <ul id="toc-Implementation-sublist" class="vector-toc-list"> <li id="toc-ISO_Prolog" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#ISO_Prolog"> <div class="vector-toc-text"> 9.1 ISO Prolog </div> </a> <ul id="toc-ISO_Prolog-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Compilation" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Compilation"> <div class="vector-toc-text"> 9.2 Compilation </div> </a> <ul id="toc-Compilation-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Tail_recursion" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Tail_recursion"> <div class="vector-toc-text"> 9.3 Tail recursion </div> </a> <ul id="toc-Tail_recursion-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Term_indexing" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Term_indexing"> <div class="vector-toc-text"> 9.4 Term indexing </div> </a> <ul id="toc-Term_indexing-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Hashing" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Hashing"> <div class="vector-toc-text"> 9.5 Hashing </div> </a> <ul id="toc-Hashing-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Tabling" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Tabling"> <div class="vector-toc-text"> 9.6 Tabling </div> </a> <ul id="toc-Tabling-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Implementation_in_hardware" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Implementation_in_hardware"> <div class="vector-toc-text"> 9.7 Implementation in hardware </div> </a> <ul id="toc-Implementation_in_hardware-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Limits" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Limits"> <div class="vector-toc-text"> 10 Limits </div> </a> <ul id="toc-Limits-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Extensions" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Extensions"> <div class="vector-toc-text"> 11 Extensions </div> </a> <button aria-controls="toc-Extensions-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Extensions subsection </button> <ul id="toc-Extensions-sublist" class="vector-toc-list"> <li id="toc-Types" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Types"> <div class="vector-toc-text"> 11.1 Types </div> </a> <ul id="toc-Types-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Modes" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Modes"> <div class="vector-toc-text"> 11.2 Modes </div> </a> <ul id="toc-Modes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Constraints" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Constraints"> <div class="vector-toc-text"> 11.3 Constraints </div> </a> <ul id="toc-Constraints-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Object-orientation" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Object-orientation"> <div class="vector-toc-text"> 11.4 Object-orientation </div> </a> <ul id="toc-Object-orientation-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Graphics" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Graphics"> <div class="vector-toc-text"> 11.5 Graphics </div> </a> <ul id="toc-Graphics-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Concurrency" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Concurrency"> <div class="vector-toc-text"> 11.6 Concurrency </div> </a> <ul id="toc-Concurrency-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Web_programming" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Web_programming"> <div class="vector-toc-text"> 11.7 Web programming </div> </a> <ul id="toc-Web_programming-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Adobe_Flash" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Adobe_Flash"> <div class="vector-toc-text"> 11.8 Adobe Flash </div> </a> <ul id="toc-Adobe_Flash-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other"> <div class="vector-toc-text"> 11.9 Other </div> </a> <ul id="toc-Other-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Interfaces_to_other_languages" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Interfaces_to_other_languages"> <div class="vector-toc-text"> 12 Interfaces to other languages </div> </a> <ul id="toc-Interfaces_to_other_languages-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> 13 History </div> </a> <ul id="toc-History-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Use_in_industry" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Use_in_industry"> <div class="vector-toc-text"> 14 Use in industry </div> </a> <ul id="toc-Use_in_industry-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> 15 See also </div> </a> <button aria-controls="toc-See_also-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle See also subsection </button> <ul id="toc-See_also-sublist" class="vector-toc-list"> <li id="toc-Related_languages" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Related_languages"> <div class="vector-toc-text"> 15.1 Related languages </div> </a> <ul id="toc-Related_languages-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> 16 Notes </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> 17 References </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> 18 Further reading </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Toggle the table of contents </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading">Prolog</h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 58 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-58" aria-hidden="true" > 58 languages </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A8%D8%B1%D9%88%D9%84%D9%88%D8%BA" title="برولوغ – Arabic" lang="ar" hreflang="ar" data-title="برولوغ" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target">العربية</a></li><li class="interlanguage-link interwiki-an mw-list-item"><a href="https://an.wikipedia.org/wiki/Prolog" title="Prolog – Aragonese" lang="an" hreflang="an" data-title="Prolog" data-language-autonym="Aragonés" data-language-local-name="Aragonese" class="interlanguage-link-target">Aragonés</a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Prolog" title="Prolog – Asturian" lang="ast" hreflang="ast" data-title="Prolog" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target">Asturianu</a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Proloq_dili" title="Proloq dili – Azerbaijani" lang="az" hreflang="az" data-title="Proloq dili" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target">Azərbaycanca</a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%9F%D1%80%D0%B0%D0%BB%D0%BE%D0%B3_(%D0%BC%D0%BE%D0%B2%D0%B0_%D0%BF%D1%80%D0%B0%D0%B3%D1%80%D0%B0%D0%BC%D0%B0%D0%B2%D0%B0%D0%BD%D0%BD%D1%8F)" title="Пралог (мова праграмавання) – Belarusian" lang="be" hreflang="be" data-title="Пралог (мова праграмавання)" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target">Беларуская</a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D0%BB%D0%BE%D0%B3_(%D0%B5%D0%B7%D0%B8%D0%BA_%D0%B7%D0%B0_%D0%BF%D1%80%D0%BE%D0%B3%D1%80%D0%B0%D0%BC%D0%B8%D1%80%D0%B0%D0%BD%D0%B5)" title="Пролог (език за програмиране) – Bulgarian" lang="bg" hreflang="bg" data-title="Пролог (език за програмиране)" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target">Български</a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Prolog" title="Prolog – Catalan" lang="ca" hreflang="ca" data-title="Prolog" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target">Català</a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Prolog_(programovac%C3%AD_jazyk)" title="Prolog (programovací jazyk) – Czech" lang="cs" hreflang="cs" data-title="Prolog (programovací jazyk)" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target">Čeština</a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Prolog_(programmeringssprog)" title="Prolog (programmeringssprog) – Danish" lang="da" hreflang="da" data-title="Prolog (programmeringssprog)" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target">Dansk</a></li><li class="interlanguage-link interwiki-pdc mw-list-item"><a href="https://pdc.wikipedia.org/wiki/Prolog" title="Prolog – Pennsylvania German" lang="pdc" hreflang="pdc" data-title="Prolog" data-language-autonym="Deitsch" data-language-local-name="Pennsylvania German" class="interlanguage-link-target">Deitsch</a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Prolog_(Programmiersprache)" title="Prolog (Programmiersprache) – German" lang="de" hreflang="de" data-title="Prolog (Programmiersprache)" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target">Deutsch</a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Prolog" title="Prolog – Estonian" lang="et" hreflang="et" data-title="Prolog" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target">Eesti</a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/Prolog" title="Prolog – Greek" lang="el" hreflang="el" data-title="Prolog" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target">Ελληνικά</a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Prolog" title="Prolog – Spanish" lang="es" hreflang="es" data-title="Prolog" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target">Español</a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Prologo_(programlingvo)" title="Prologo (programlingvo) – Esperanto" lang="eo" hreflang="eo" data-title="Prologo (programlingvo)" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target">Esperanto</a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Prolog" title="Prolog – Basque" lang="eu" hreflang="eu" data-title="Prolog" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target">Euskara</a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D9%84%D9%88%DA%AF" title="پرولوگ – Persian" lang="fa" hreflang="fa" data-title="پرولوگ" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target">فارسی</a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Prolog" title="Prolog – French" lang="fr" hreflang="fr" data-title="Prolog" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target">Français</a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Prolog" title="Prolog – Irish" lang="ga" hreflang="ga" data-title="Prolog" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target">Gaeilge</a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Prolog" title="Prolog – Galician" lang="gl" hreflang="gl" data-title="Prolog" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target">Galego</a></li><li class="interlanguage-link interwiki-hak mw-list-item"><a href="https://hak.wikipedia.org/wiki/Prolog" title="Prolog – Hakka Chinese" lang="hak" hreflang="hak" data-title="Prolog" data-language-autonym="客家語 / Hak-kâ-ngî" data-language-local-name="Hakka Chinese" class="interlanguage-link-target">客家語 / Hak-kâ-ngî</a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%ED%94%84%EB%A1%A4%EB%A1%9C%EA%B7%B8_(%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%B0%8D_%EC%96%B8%EC%96%B4)" title="프롤로그 (프로그래밍 언어) – Korean" lang="ko" hreflang="ko" data-title="프롤로그 (프로그래밍 언어)" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target">한국어</a></li><li class="interlanguage-link interwiki-io mw-list-item"><a href="https://io.wikipedia.org/wiki/Prolog" title="Prolog – Ido" lang="io" hreflang="io" data-title="Prolog" data-language-autonym="Ido" data-language-local-name="Ido" class="interlanguage-link-target">Ido</a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Prolog" title="Prolog – Indonesian" lang="id" hreflang="id" data-title="Prolog" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target">Bahasa Indonesia</a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Prolog" title="Prolog – Icelandic" lang="is" hreflang="is" data-title="Prolog" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target">Íslenska</a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Prolog" title="Prolog – Italian" lang="it" hreflang="it" data-title="Prolog" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target">Italiano</a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A4%D7%A8%D7%95%D7%9C%D7%95%D7%92_(%D7%A9%D7%A4%D7%AA_%D7%AA%D7%9B%D7%A0%D7%95%D7%AA)" title="פרולוג (שפת תכנות) – Hebrew" lang="he" hreflang="he" data-title="פרולוג (שפת תכנות)" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target">עברית</a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Prolog" title="Prolog – Latvian" lang="lv" hreflang="lv" data-title="Prolog" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target">Latviešu</a></li><li class="interlanguage-link interwiki-jbo mw-list-item"><a href="https://jbo.wikipedia.org/wiki/prolog" title="prolog – Lojban" lang="jbo" hreflang="jbo" data-title="prolog" data-language-autonym="La .lojban." data-language-local-name="Lojban" class="interlanguage-link-target">La .lojban.</a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Prolog" title="Prolog – Hungarian" lang="hu" hreflang="hu" data-title="Prolog" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target">Magyar</a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D0%BB%D0%BE%D0%B3_(%D0%BF%D1%80%D0%BE%D0%B3%D1%80%D0%B0%D0%BC%D1%81%D0%BA%D0%B8_%D1%98%D0%B0%D0%B7%D0%B8%D0%BA)" title="Пролог (програмски јазик) – Macedonian" lang="mk" hreflang="mk" data-title="Пролог (програмски јазик)" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target">Македонски</a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Prolog" title="Prolog – Malay" lang="ms" hreflang="ms" data-title="Prolog" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target">Bahasa Melayu</a></li><li class="interlanguage-link interwiki-nl badge-Q17437796 badge-featuredarticle mw-list-item" title="featured article badge"><a href="https://nl.wikipedia.org/wiki/Prolog" title="Prolog – Dutch" lang="nl" hreflang="nl" data-title="Prolog" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target">Nederlands</a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/Prolog" title="Prolog – Japanese" lang="ja" hreflang="ja" data-title="Prolog" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target">日本語</a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Prolog_(programmeringsspr%C3%A5k)" title="Prolog (programmeringsspråk) – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Prolog (programmeringsspråk)" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target">Norsk bokmål</a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Programmeringsspr%C3%A5ket_Prolog" title="Programmeringsspråket Prolog – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Programmeringsspråket Prolog" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target">Norsk nynorsk</a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Prolog" title="Prolog – Uzbek" lang="uz" hreflang="uz" data-title="Prolog" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target">Oʻzbekcha / ўзбекча</a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Prolog_(j%C4%99zyk_programowania)" title="Prolog (język programowania) – Polish" lang="pl" hreflang="pl" data-title="Prolog (język programowania)" 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href="https://rue.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D0%BB%D0%BE%D2%91_(%D1%8F%D0%B7%D1%8B%D0%BA_%D0%BF%D1%80%D0%BE%D2%91%D1%80%D0%B0%D0%BC%D0%BE%D0%B2%D0%B0%D0%BD%D1%8F)" title="Пролоґ (язык проґрамованя) – Rusyn" lang="rue" hreflang="rue" data-title="Пролоґ (язык проґрамованя)" data-language-autonym="Русиньскый" data-language-local-name="Rusyn" class="interlanguage-link-target">Русиньскый</a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D0%BB%D0%BE%D0%B3_(%D1%8F%D0%B7%D1%8B%D0%BA_%D0%BF%D1%80%D0%BE%D0%B3%D1%80%D0%B0%D0%BC%D0%BC%D0%B8%D1%80%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F)" title="Пролог (язык программирования) – Russian" lang="ru" hreflang="ru" data-title="Пролог (язык программирования)" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target">Русский</a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Prolog" title="Prolog – Simple English" lang="en-simple" hreflang="en-simple" data-title="Prolog" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target">Simple English</a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Prolog" title="Prolog – Slovak" lang="sk" hreflang="sk" data-title="Prolog" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target">Slovenčina</a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Prolog_(programski_jezik)" title="Prolog (programski jezik) – Slovenian" lang="sl" hreflang="sl" data-title="Prolog (programski jezik)" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target">Slovenščina</a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a 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data-title="Пролог (забони барноманависӣ)" data-language-autonym="Тоҷикӣ" data-language-local-name="Tajik" class="interlanguage-link-target">Тоҷикӣ</a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Prolog" title="Prolog – Turkish" lang="tr" hreflang="tr" data-title="Prolog" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target">Türkçe</a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D0%BB%D0%BE%D0%B3_(%D0%BC%D0%BE%D0%B2%D0%B0_%D0%BF%D1%80%D0%BE%D0%B3%D1%80%D0%B0%D0%BC%D1%83%D0%B2%D0%B0%D0%BD%D0%BD%D1%8F)" title="Пролог (мова програмування) – Ukrainian" lang="uk" hreflang="uk" data-title="Пролог (мова програмування)" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target">Українська</a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Prolog" title="Prolog – Vietnamese" lang="vi" hreflang="vi" data-title="Prolog" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target">Tiếng Việt</a></li><li class="interlanguage-link interwiki-yo mw-list-item"><a href="https://yo.wikipedia.org/wiki/Prolog" title="Prolog – Yoruba" lang="yo" hreflang="yo" data-title="Prolog" data-language-autonym="Yorùbá" data-language-local-name="Yoruba" class="interlanguage-link-target">Yorùbá</a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/Prolog" title="Prolog – Cantonese" lang="yue" hreflang="yue" data-title="Prolog" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target">粵語</a></li><li class="interlanguage-link interwiki-bat-smg mw-list-item"><a href="https://bat-smg.wikipedia.org/wiki/Prolog" title="Prolog – Samogitian" lang="sgs" hreflang="sgs" 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<div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Programming language that uses first order logic</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">This article is about the programming language. For the narrative device, see <a href="/wiki/Prologue" title="Prologue">Prologue</a>. For other uses, see <a href="/wiki/Prologue_(disambiguation)" class="mw-disambig" title="Prologue (disambiguation)">Prologue (disambiguation)</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox vevent"><caption class="infobox-title summary">Prolog</caption><tbody><tr><th scope="row" class="infobox-label"><a href="/wiki/Programming_paradigm" title="Programming paradigm">Paradigm</a></th><td class="infobox-data"><a href="/wiki/Logic_programming" title="Logic programming">Logic</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Software_design" title="Software design">Designed by</a></th><td class="infobox-data"><a href="/wiki/Alain_Colmerauer" title="Alain Colmerauer">Alain Colmerauer</a></td></tr><tr><th scope="row" class="infobox-label">First appeared</th><td class="infobox-data">1972; 52 years ago (1972)</td></tr><tr><td colspan="2" class="infobox-full-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1257001546"></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Software_release_life_cycle" title="Software release life cycle">Stable release</a></th><td class="infobox-data"><div style="margin:0px;">Part 1: General core-Edition 1 (June 1995; 29 years ago (1995-06)) Part 2: Modules-Edition 1 (June 2000; 24 years ago (2000-06)) </div></td></tr><tr style="display:none"><td colspan="2"> </td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Type_system" title="Type system">Typing discipline</a></th><td class="infobox-data">Untyped (its single data type is "term")</td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Filename_extension" title="Filename extension">Filename extensions</a></th><td class="infobox-data"><code>.pl</code>, <code>.pro</code>, <code>.P</code></td></tr><tr><th scope="row" class="infobox-label">Website</th><td class="infobox-data">Part 1: <a rel="nofollow" class="external text" href="https://www.iso.org/standard/21413.html">www.iso.org/standard/21413.html</a> Part 2: <a rel="nofollow" class="external text" href="https://www.iso.org/standard/20775.html">www.iso.org/standard/20775.html</a></td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #eee;">Major <a href="/wiki/Programming_language_implementation" title="Programming language implementation">implementations</a></th></tr><tr><td colspan="2" class="infobox-full-data"><a rel="nofollow" class="external text" href="http://www.amzi.com/#apls">Amzi! Prolog</a>, <a href="/wiki/B-Prolog" title="B-Prolog">B-Prolog</a>, <a href="/wiki/Ciao_(programming_language)" title="Ciao (programming language)">Ciao</a>, <a href="/wiki/ECLiPSe" title="ECLiPSe">ECLiPSe</a>, <a href="/wiki/GNU_Prolog" title="GNU Prolog">GNU Prolog</a>, <a href="/wiki/Logic_Programming_Associates" title="Logic Programming Associates">LPA Prolog</a>, <a href="/wiki/Poplog" title="Poplog">Poplog</a>, <a rel="nofollow" class="external text" href="https://homepages.inf.ed.ac.uk/stg/research/Psharp/">P#</a>, <a href="/wiki/Quintus_Prolog" title="Quintus Prolog">Quintus Prolog</a>, <a rel="nofollow" class="external text" href="https://www.scryer.pl/">Scryer Prolog</a>, <a rel="nofollow" class="external text" href="https://sicstus.sics.se/">SICStus</a>, <a rel="nofollow" class="external text" href="https://dobrev.com/">Strawberry</a>, <a href="/wiki/SWI-Prolog" title="SWI-Prolog">SWI-Prolog</a>, <a rel="nofollow" class="external text" href="http://tau-prolog.org/">Tau Prolog</a>, <a rel="nofollow" class="external text" href="http://tuprolog.unibo.it/">tuProlog</a>, <a rel="nofollow" class="external text" href="https://www.lpa.co.uk/win.htm">WIN-PROLOG</a> <a href="/wiki/XSB" title="XSB">XSB</a>, <a href="/wiki/YAP_(Prolog)" title="YAP (Prolog)">YAP</a>.</td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #eee;"><a href="/wiki/Programming_language#Dialects,_flavors_and_implementations" title="Programming language">Dialects</a></th></tr><tr><td colspan="2" class="infobox-full-data"><a href="#ISO_Prolog">ISO Prolog</a>, Edinburgh Prolog</td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #eee;">Influenced by</th></tr><tr><td colspan="2" class="infobox-full-data"><a href="/wiki/Planner_(programming_language)" title="Planner (programming language)">Planner</a></td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #eee;">Influenced</th></tr><tr><td colspan="2" class="infobox-full-data"><a href="/wiki/Constraint_Handling_Rules" title="Constraint Handling Rules">CHR</a>, <a href="/wiki/Clojure" title="Clojure">Clojure</a>, <a href="/wiki/Datalog" title="Datalog">Datalog</a>, <a href="/wiki/Erlang_(programming_language)" title="Erlang (programming language)">Erlang</a>, <a rel="nofollow" class="external text" href="http://epilog.stanford.edu/">Epilog</a>, <a href="/wiki/KL0" title="KL0">KL0</a>, <a href="/wiki/KL1" title="KL1">KL1</a>, <a href="/wiki/Logtalk" title="Logtalk">Logtalk</a>, <a href="/wiki/Mercury_(programming_language)" title="Mercury (programming language)">Mercury</a>, <a href="/wiki/Oz_(programming_language)" title="Oz (programming language)">Oz</a>, <a href="/wiki/Strand_(programming_language)" title="Strand (programming language)">Strand</a>, <a href="/wiki/Visual_Prolog" title="Visual Prolog">Visual Prolog</a></td></tr><tr><td colspan="2" class="infobox-below hlist" style="border-top: 1px solid #aaa; padding-top: 3px;"> <ul><li><a href="/wiki/File:Wikibooks-logo-en-noslogan.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/df/Wikibooks-logo-en-noslogan.svg/16px-Wikibooks-logo-en-noslogan.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/df/Wikibooks-logo-en-noslogan.svg/24px-Wikibooks-logo-en-noslogan.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/df/Wikibooks-logo-en-noslogan.svg/32px-Wikibooks-logo-en-noslogan.svg.png 2x" data-file-width="400" data-file-height="400" /></a> <a href="https://en.wikibooks.org/wiki/Prolog" class="extiw" title="wikibooks:Prolog">Prolog</a> at Wikibooks</li></ul> </td></tr></tbody></table> Prolog is a <a href="/wiki/Logic_programming" title="Logic programming">logic programming</a> language that has its origins in <a href="/wiki/Artificial_intelligence" title="Artificial intelligence">artificial intelligence</a>, <a href="/wiki/Automated_theorem_proving" title="Automated theorem proving">automated theorem proving</a> and <a href="/wiki/Computational_linguistics" title="Computational linguistics">computational linguistics</a>.<a href="#cite_note-Clocksin2003-1">[1]</a><a href="#cite_note-Bratko2012-2">[2]</a><a href="#cite_note-Covington1994-3">[3]</a> Prolog has its roots in <a href="/wiki/First-order_logic" title="First-order logic">first-order logic</a>, a <a href="/wiki/Formal_logic" class="mw-redirect" title="Formal logic">formal logic</a>, and unlike many other <a href="/wiki/Programming_language" title="Programming language">programming languages</a>, Prolog is intended primarily as a <a href="/wiki/Declarative_programming" title="Declarative programming">declarative programming</a> language: the program is a set of facts and <a href="/wiki/Horn_clause" title="Horn clause">rules</a>, which define <a href="/wiki/Finitary_relation" title="Finitary relation">relations</a>. A <a href="/wiki/Computation" title="Computation">computation</a> is initiated by running a query over the program.<a href="#cite_note-lloyd84-4">[4]</a> Prolog was one of the first logic programming languages<a href="#cite_note-5">[5]</a> and remains the most popular such language today, with several free and commercial implementations available. The language has been used for <a href="/wiki/Automated_theorem_proving" title="Automated theorem proving">theorem proving</a>,<a href="#cite_note-6">[6]</a> <a href="/wiki/Expert_system" title="Expert system">expert systems</a>,<a href="#cite_note-7">[7]</a> <a href="/wiki/Term_rewriting" class="mw-redirect" title="Term rewriting">term rewriting</a>,<a href="#cite_note-8">[8]</a> <a href="/wiki/Type_system" title="Type system">type systems</a>,<a href="#cite_note-Lee2015-9">[9]</a> and <a href="/wiki/Automated_planning" class="mw-redirect" title="Automated planning">automated planning</a>,<a href="#cite_note-Schmid2003-10">[10]</a> as well as its original intended field of use, <a href="/wiki/Natural_language_processing" title="Natural language processing">natural language processing</a>.<a href="#cite_note-11">[11]</a><a href="#cite_note-lally-12">[12]</a> Prolog is a Turing-complete, general-purpose programming language, which is well-suited for intelligent knowledge-processing applications. <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Syntax_and_semantics">Syntax and semantics</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=1" title="Edit section: Syntax and semantics">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Prolog_syntax_and_semantics" title="Prolog syntax and semantics">Prolog syntax and semantics</a></div> In Prolog, program logic is expressed in terms of relations, and a computation is initiated by running a query over these relations. Relations and queries are constructed using Prolog's single data type, the term.<a href="#cite_note-lloyd84-4">[4]</a> Relations are defined by clauses. Given a query, the Prolog engine attempts to find a <a href="/wiki/Resolution_(logic)" title="Resolution (logic)">resolution</a> <a href="/wiki/Refutation" class="mw-redirect" title="Refutation">refutation</a> of the negated query. If the negated query can be refuted, i.e., an instantiation for all free variables is found that makes the union of clauses and the singleton set consisting of the negated query false, it follows that the original query, with the found instantiation applied, is a <a href="/wiki/Logical_consequence" title="Logical consequence">logical consequence</a> of the program. This makes Prolog (and other logic programming languages) particularly useful for database, <a href="/wiki/Symbolic_mathematics" class="mw-redirect" title="Symbolic mathematics">symbolic mathematics</a>, and language parsing applications. Because Prolog allows impure <a href="/wiki/Predicate_(mathematical_logic)" title="Predicate (mathematical logic)">predicates</a>, checking the <a href="/wiki/Truth_value" title="Truth value">truth value</a> of certain special predicates may have some deliberate <a href="/wiki/Side_effect_(computer_science)" title="Side effect (computer science)">side effect</a>, such as printing a value to the screen. Because of this, the programmer is permitted to use some amount of conventional <a href="/wiki/Imperative_programming" title="Imperative programming">imperative programming</a> when the logical paradigm is inconvenient. It has a purely logical subset, called "pure Prolog", as well as a number of extralogical features. <div class="mw-heading mw-heading3"><h3 id="Data_types">Data types</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=2" title="Edit section: Data types">edit</a>]</div> Prolog's single <a href="/wiki/Data_type" title="Data type">data type</a> is the term. Terms are either <a href="/wiki/Symbol_(programming)#Prolog" title="Symbol (programming)">atoms</a>, numbers, variables or compound terms.<a href="#cite_note-13">[note 1]</a> <ul><li>An atom is a symbol name starting with a lower case letter or guarded by quotes. Examples of atoms include <code>x</code>, <code>red</code>, <code>'Taco'</code>, <code>'some atom'</code>, and <code>'p(a)'</code>.</li> <li>Numbers can be <a href="/wiki/Floating-point_arithmetic" title="Floating-point arithmetic">floats</a> or <a href="/wiki/Integer" title="Integer">integers</a>. Most of the major Prolog systems support arbitrary length integer numbers.</li> <li>Variables are denoted by a string consisting of letters, numbers and underscore characters, and beginning with an upper-case letter or underscore. Variables closely resemble variables in logic in that they are placeholders for arbitrary terms.</li> <li>A compound term is composed of an atom called a "functor" and a number of "arguments", which are again terms. Compound terms are ordinarily written as a functor followed by a comma-separated list of argument terms, which is contained in parentheses. The number of arguments is called the term's <a href="/wiki/Arity" title="Arity">arity</a>. An atom can be regarded as a compound term with <a href="/wiki/Arity" title="Arity">arity</a> zero. An example of a compound term is <code>person_friends(zelda,[tom,jim])</code>.</li></ul> Special cases of compound terms: <ul><li>A List is an ordered collection of terms. It is denoted by square brackets with the terms separated by commas, or in the case of the empty list, by <code>[]</code>. For example, <code>[1,2,3,4]</code> or <code>[red,green,blue]</code>.</li> <li>Strings: A sequence of characters surrounded by quotes is equivalent to either a list of (numeric) character codes, a list of characters (atoms of length 1), or an atom depending on the value of the Prolog flag <code>double_quotes</code>. For example, <code>"to be, or not to be"</code>.<a href="#cite_note-ISO_13211-1_6.3.7-14">[13]</a></li></ul> <div class="mw-heading mw-heading3"><h3 id="Rules_and_facts">Rules and facts</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=3" title="Edit section: Rules and facts">edit</a>]</div> Prolog programs describe relations, defined by means of clauses. Pure Prolog is restricted to <a href="/wiki/Horn_clause" title="Horn clause">Horn clauses</a>. Two types of Horn clauses are used to define Prolog programs: rules and facts. A rule is of the form <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>Head :- Body. </pre></div> and is read as "Head is true if Body is true". A rule's body consists of calls to predicates, which are called the rule's goals. The built-in <a href="/wiki/Logical_operator" class="mw-redirect" title="Logical operator">logical operator</a> <code>,/2</code> (meaning an arity 2 <a href="/wiki/Operator_(programming)" class="mw-redirect" title="Operator (programming)">operator</a> with name <code>,</code>) denotes <a href="/wiki/Logical_conjunction" title="Logical conjunction">conjunction</a> of goals, and <code>;/2</code> denotes <a href="/wiki/Logical_disjunction" title="Logical disjunction">disjunction</a>. Conjunctions and disjunctions can only appear in the body, not in the head of a rule. Clauses with empty bodies are called facts. An example of a fact is: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>human(socrates). </pre></div> which is equivalent to the rule: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>human(socrates) :- true. </pre></div> The built-in predicate <code>true/0</code> is always true. Given the above fact, one can ask: is socrates a human? <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre> ?- human(socrates). Yes </pre></div> what things are humans? <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre> ?- human(X). X = socrates </pre></div> Clauses with bodies are called rules. An example of a rule is: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>mortal(X) :- human(X). </pre></div> If we add that rule and ask what things are mortals? <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre> ?- mortal(X). X = socrates </pre></div> <div class="mw-heading mw-heading3"><h3 id="Predicates_and_programs">Predicates and programs</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=4" title="Edit section: Predicates and programs">edit</a>]</div> A predicate (or procedure definition) is a collection of clauses whose heads have the same name and arity. We use the notation name/arity to refer to predicates. A logic program is a set of predicates. For example, the following Prolog program, which defines some family relations, has four predicates: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>mother_child(trude, sally). father_child(tom, sally). father_child(tom, erica). father_child(mike, tom). sibling(X, Y) :- parent_child(Z, X), parent_child(Z, Y). parent_child(X, Y) :- father_child(X, Y). parent_child(X, Y) :- mother_child(X, Y). </pre></div> Predicate <code>father_child/2</code> has three clauses, all of which are facts, and predicate <code>parent_child/2</code> has two clauses, both are rules. Due to the relational nature of many built-in predicates, they can typically be used in several directions. For example, <code>length/2</code> can be used to determine the length of a list (<code>length(List, L)</code>, given a list <code>List</code>), and to generate a list skeleton of a given length (<code>length(X, 5)</code>), and to generate both list skeletons and their lengths together (<code>length(X, L)</code>). Similarly, <code>append/3</code> can be used both to append two lists (<code>append(ListA, ListB, X)</code> given lists <code>ListA</code> and <code>ListB</code>), and to split a given list into parts (<code>append(X, Y, List)</code>, given a list <code>List</code>). For this reason, a comparatively small set of library predicates suffices for many Prolog programs. As a general purpose language, Prolog also provides various built-in predicates to perform routine activities like <a href="/wiki/Input/output" title="Input/output">input/output</a>, using graphics and otherwise communicating with the operating system. These predicates are not given a relational meaning and are only useful for the side-effects they exhibit on the system. For example, the predicate <code>write/1</code> displays a term on the screen. <div class="mw-heading mw-heading3"><h3 id="Loops_and_recursion">Loops and recursion</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=5" title="Edit section: Loops and recursion">edit</a>]</div> Iterative algorithms can be implemented by means of recursive predicates.<a href="#cite_note-15">[14]</a> Consider the <code>parent_child/2</code> predicate defined in the family relation program above. The following Prolog program defines the ancestor relation:<div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>ancestor(X, Y) :- parent_child(X, Y). ancestor(X, Y) :- parent_child(X, Z), ancestor(Z, Y). </pre></div>It expresses that X is an ancestor of Y if X is parent of Y or X is parent of an ancestor of Y. It is recursive because it is defined in terms of itself (there is a call to predicate <code>ancestor/2</code> in the body of the second clause). <div class="mw-heading mw-heading3"><h3 id="Execution">Execution</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=6" title="Edit section: Execution">edit</a>]</div> Execution of a Prolog program is initiated by the user's posting of a single goal, called the query. Logically, the Prolog engine tries to find a <a href="/wiki/Resolution_(logic)" title="Resolution (logic)">resolution</a> refutation of the negated query. The resolution method used by Prolog is called <a href="/wiki/SLD_resolution" title="SLD resolution">SLD resolution</a>. If the negated query can be refuted, it follows that the query, with the appropriate variable bindings in place, is a logical consequence of the program. In that case, all generated variable bindings are reported to the user, and the query is said to have succeeded. Operationally, Prolog's execution strategy can be thought of as a generalization of function calls in other languages, one difference being that multiple clause heads can match a given call. In that case, the system creates a choice-point, <a href="/wiki/Unification_(computer_science)" title="Unification (computer science)">unifies</a> the goal with the clause head of the first alternative, and continues with the goals of that first alternative. If any goal fails in the course of executing the program, all variable bindings that were made since the most recent choice-point was created are undone, and execution continues with the next alternative of that choice-point. This execution strategy is called chronological <a href="/wiki/Backtracking" title="Backtracking">backtracking</a>. For example, given the family relation program defined above, the following query will be evaluated to true: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre> ?- sibling(sally, erica). Yes </pre></div> This is obtained as follows: Initially, the only matching clause-head for the query <code>sibling(sally, erica)</code> is the first one, so proving the query is equivalent to proving the body of that clause with the appropriate variable bindings in place, i.e., the conjunction <code>(parent_child(Z,sally), parent_child(Z,erica))</code>. The next goal to be proved is the leftmost one of this conjunction, i.e., <code>parent_child(Z, sally)</code>. Two clause heads match this goal. The system creates a choice-point and tries the first alternative, whose body is <code>father_child(Z, sally)</code>. This goal can be proved using the fact <code>father_child(tom, sally)</code>, so the binding <code>Z = tom</code> is generated, and the next goal to be proved is the second part of the above conjunction: <code>parent_child(tom, erica)</code>. Again, this can be proved by the corresponding fact. Since all goals could be proved, the query succeeds. Since the query contained no variables, no bindings are reported to the user. A query with variables, like: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>?- father_child(Father, Child). </pre></div> enumerates all valid answers on backtracking. Notice that with the code as stated above, the query <code>?- sibling(sally, sally).</code> also succeeds. One would insert additional goals to describe the relevant restrictions, if desired. <div class="mw-heading mw-heading3"><h3 id="Negation">Negation</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=7" title="Edit section: Negation">edit</a>]</div> The built-in Prolog predicate <code>\+/1</code> provides <a href="/wiki/Negation_as_failure" title="Negation as failure">negation as failure</a>, which allows for <a href="/wiki/Non-monotonic_logic" title="Non-monotonic logic">non-monotonic</a> reasoning. The goal <code>\+ illegal(X)</code> in the rule <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>legal(X) :- \+ illegal(X). </pre></div> is evaluated as follows: Prolog attempts to prove <code>illegal(X)</code>. If a proof for that goal can be found, the original goal (i.e., <code>\+ illegal(X)</code>) fails. If no proof can be found, the original goal succeeds. Therefore, the <code>\+/1</code> prefix operator is called the "not provable" operator, since the query <code>?- \+ Goal.</code> succeeds if Goal is not provable. This kind of negation is <a href="/wiki/Soundness" title="Soundness">sound</a> if its argument is <a href="/wiki/Ground_expression" title="Ground expression">"ground"</a> (i.e. contains no variables). Soundness is lost if the argument contains variables and the proof procedure is complete. In particular, the query <code>?- legal(X).</code> now cannot be used to enumerate all things that are legal. <div class="mw-heading mw-heading2"><h2 id="Programming_in_Prolog">Programming in Prolog</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=8" title="Edit section: Programming in Prolog">edit</a>]</div> In Prolog, loading code is referred to as consulting. Prolog can be used interactively by entering queries at the Prolog prompt <code>?-</code>. If there is no solution, Prolog writes <code>no</code>. If a solution exists then it is printed. If there are multiple solutions to the query, then these can be requested by entering a semi-colon <code>;</code>. There are guidelines on good programming practice to improve code efficiency, readability and maintainability.<a href="#cite_note-16">[15]</a> Here follow some example programs written in Prolog. <div class="mw-heading mw-heading3"><h3 id="Hello_World">Hello World</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=9" title="Edit section: Hello World">edit</a>]</div> Example of a basic query in a couple of popular Prolog dialects: <table> <tbody><tr> <th><a href="/wiki/SWI-Prolog" title="SWI-Prolog">SWI-Prolog</a> </th> <th><a href="/wiki/GNU_Prolog" title="GNU Prolog">GNU Prolog</a> </th></tr> <tr> <td><div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>?- write('Hello World!'), nl. Hello World! true. ?- </pre></div> </td> <td><div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>| ?- write('Hello World!'), nl. Hello World! yes | ?- </pre></div> </td></tr></tbody></table> This comparison shows the prompt ("?-" vs "| ?-") and resolution status ("true." vs "yes", "false." vs "no") can differ from one Prolog implementation to another. <div class="mw-heading mw-heading3"><h3 id="Compiler_optimization">Compiler optimization</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=10" title="Edit section: Compiler optimization">edit</a>]</div> Any computation can be expressed declaratively as a sequence of state transitions. As an example, an <a href="/wiki/Optimizing_compiler" title="Optimizing compiler">optimizing compiler</a> with three optimization passes could be implemented as a relation between an initial program and its optimized form: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>program_optimized(Prog0, Prog) :- optimization_pass_1(Prog0, Prog1), optimization_pass_2(Prog1, Prog2), optimization_pass_3(Prog2, Prog). </pre></div> or equivalently using <a href="/wiki/Definite_clause_grammar" title="Definite clause grammar">DCG</a> notation: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>program_optimized --> optimization_pass_1, optimization_pass_2, optimization_pass_3. </pre></div> <div class="mw-heading mw-heading3"><h3 id="Quicksort">Quicksort</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=11" title="Edit section: Quicksort">edit</a>]</div> The <a href="/wiki/Quicksort" title="Quicksort">quicksort</a> sorting algorithm, relating a list to its sorted version: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>partition([], _, [], []). partition([X|Xs], Pivot, Smalls, Bigs) :- ( X @< Pivot -> Smalls = [X|Rest], partition(Xs, Pivot, Rest, Bigs) ; Bigs = [X|Rest], partition(Xs, Pivot, Smalls, Rest) ). quicksort([]) --> []. quicksort([X|Xs]) --> { partition(Xs, X, Smaller, Bigger) }, quicksort(Smaller), [X], quicksort(Bigger). </pre></div> <div class="mw-heading mw-heading2"><h2 id="Design_patterns_of_Prolog">Design patterns of Prolog</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=12" title="Edit section: Design patterns of Prolog">edit</a>]</div> A <a href="/wiki/Design_pattern_(computer_science)" class="mw-redirect" title="Design pattern (computer science)">design pattern</a> is a general reusable solution to a commonly occurring problem in <a href="/wiki/Software_design" title="Software design">software design</a>. Some design patterns in Prolog are skeletons, techniques,<a href="#cite_note-17">[16]</a><a href="#cite_note-18">[17]</a> cliches,<a href="#cite_note-19">[18]</a> program schemata,<a href="#cite_note-Gegg-harrison1995-20">[19]</a> logic description schemata,<a href="#cite_note-Deville1990-21">[20]</a> and <a href="/wiki/Higher-order_programming" title="Higher-order programming">higher-order programming</a>.<a href="#cite_note-Naish1996-22">[21]</a> <div class="mw-heading mw-heading2"><h2 id="Higher-order_programming">Higher-order programming</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=13" title="Edit section: Higher-order programming">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Higher-order_logic" title="Higher-order logic">Higher-order logic</a> and <a href="/wiki/Higher-order_programming" title="Higher-order programming">Higher-order programming</a></div> A higher-order predicate is a predicate that takes one or more other predicates as arguments. Although support for higher-order programming takes Prolog outside the domain of first-order logic, which does not allow quantification over predicates,<a href="#cite_note-23">[22]</a> ISO Prolog now has some built-in higher-order predicates such as <code>call/1</code>, <code>call/2</code>, <code>call/3</code>, <code>findall/3</code>, <code>setof/3</code>, and <code>bagof/3</code>.<a href="#cite_note-ISO_13211-24">[23]</a> Furthermore, since arbitrary Prolog goals can be constructed and evaluated at run-time, it is easy to write higher-order predicates like <code>maplist/2</code>, which applies an arbitrary predicate to each member of a given list, and <code>sublist/3</code>, which filters elements that satisfy a given predicate, also allowing for <a href="/wiki/Currying" title="Currying">currying</a>.<a href="#cite_note-Naish1996-22">[21]</a> To convert solutions from temporal representation (answer substitutions on backtracking) to spatial representation (terms), Prolog has various all-solutions predicates that collect all answer substitutions of a given query in a list. This can be used for <a href="/wiki/List_comprehension" title="List comprehension">list comprehension</a>. For example, <a href="/wiki/Perfect_numbers" class="mw-redirect" title="Perfect numbers">perfect numbers</a> equal the sum of their proper divisors: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre> perfect(N) :- between(1, inf, N), U is N // 2, findall(D, (between(1,U,D), N mod D =:= 0), Ds), sumlist(Ds, N). </pre></div> This can be used to enumerate perfect numbers, and to check if a number is perfect. As another example, the predicate <code>maplist</code> applies a predicate <code>P</code> to all corresponding positions in a pair of lists: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>maplist(_, [], []). maplist(P, [X|Xs], [Y|Ys]) :- call(P, X, Y), maplist(P, Xs, Ys). </pre></div> When <code>P</code> is a predicate that for all <code>X</code>, <code>P(X,Y)</code> unifies <code>Y</code> with a single unique value, <code>maplist(P, Xs, Ys)</code> is equivalent to applying the <a href="/wiki/Map_(higher-order_function)" title="Map (higher-order function)">map</a> function in <a href="/wiki/Functional_programming" title="Functional programming">functional programming</a> as <code>Ys = map(Function, Xs)</code>. Higher-order programming style in Prolog was pioneered in <a href="/wiki/HiLog" title="HiLog">HiLog</a> and <a href="/wiki/%CE%9BProlog" title="ΛProlog">λProlog</a>. <div class="mw-heading mw-heading2"><h2 id="Modules">Modules</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=14" title="Edit section: Modules">edit</a>]</div> For <a href="/wiki/Programming_in_the_large_and_programming_in_the_small#Programming_in_the_large" title="Programming in the large and programming in the small">programming in the large</a>, Prolog provides a <a href="/wiki/Modular_programming" title="Modular programming">module system</a>, which is in the ISO Standard.<a href="#cite_note-25">[24]</a> However, while most Prolog systems support structuring the code into modules, virtually no implementation adheres to the modules part of the ISO standard. Instead, most <a href="/wiki/Comparison_of_Prolog_implementations" title="Comparison of Prolog implementations">Prolog systems</a> have decided to support as de-facto module standard the <a href="/wiki/Quintus_Prolog" title="Quintus Prolog">Quintus</a>/<a href="/wiki/SICStus" class="mw-redirect" title="SICStus">SICStus</a> module system. However, further convenience predicates concerning modules are provided by some implementations only and often have subtle differences in their semantics.<a href="#cite_note-auto-26">[25]</a> Some systems chose to implement module concepts as source-to-source compilation into base ISO Prolog, as is the case of <a href="/wiki/Logtalk" title="Logtalk">Logtalk</a>.<a href="#cite_note-cs.kuleuven.ac.be-27">[26]</a> GNU Prolog initially diverted from ISO modules, opting instead for <a href="/w/index.php?title=Contextual_Logic_Programming&action=edit&redlink=1" class="new" title="Contextual Logic Programming (page does not exist)">Contextual Logic Programming</a>, in which unit (module) loading and unloading can be made dynamically.<a href="#cite_note-28">[27]</a> <a href="/wiki/Ciao_(programming_language)" title="Ciao (programming language)">Ciao</a> designed a strict module system that, while being basically compatible with the de-facto standard used by other Prolog systems, is amenable to precise static analysis, supports term hiding, and facilitates programming in the large.<a href="#cite_note-29">[28]</a> <a href="/wiki/XSB" title="XSB">XSB</a> takes a different approach and offers an atom-based module system.<a href="#cite_note-30">[29]</a> The latter two Prolog systems allow controlling the visibility of terms in addition to that of predicates.<a href="#cite_note-auto-26">[25]</a> <div class="mw-heading mw-heading2"><h2 id="Parsing">Parsing</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=15" title="Edit section: Parsing">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Prolog_syntax_and_semantics#Definite_clause_grammars" title="Prolog syntax and semantics">Prolog syntax and semantics § Definite clause grammars</a>, and <a href="/wiki/Definite_clause_grammar" title="Definite clause grammar">Definite clause grammar</a></div> There is a special notation called <a href="/wiki/Definite_clause_grammar" title="Definite clause grammar">definite clause grammars</a> (DCGs). A rule defined via <code>-->/2</code> instead of <code>:-/2</code> is expanded by the preprocessor (<code>expand_term/2</code>, a facility analogous to macros in other languages) according to a few straightforward rewriting rules, resulting in ordinary Prolog clauses. Most notably, the rewriting equips the predicate with two additional arguments, which can be used to implicitly thread state around,[<a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify">clarification needed</a>] analogous to <a href="/wiki/Monads_in_functional_programming" class="mw-redirect" title="Monads in functional programming">monads</a> in other languages. DCGs are often used to write parsers or list generators, as they also provide a convenient interface to difference lists. <div class="mw-heading mw-heading2"><h2 id="Meta-interpreters_and_reflection">Meta-interpreters and reflection</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=16" title="Edit section: Meta-interpreters and reflection">edit</a>]</div> Prolog is a <a href="/wiki/Homoiconic" class="mw-redirect" title="Homoiconic">homoiconic</a> language and provides many facilities for <a href="/wiki/Reflective_programming" title="Reflective programming">reflective programming</a> (reflection). Its implicit execution strategy makes it possible to write a concise <a href="/wiki/Meta-circular_evaluator" title="Meta-circular evaluator">meta-circular evaluator</a> (also called meta-interpreter) for pure Prolog code: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>solve(true). solve((Subgoal1,Subgoal2)) :- solve(Subgoal1), solve(Subgoal2). solve(Head) :- clause(Head, Body), solve(Body). </pre></div> where <code>true</code> represents an empty conjunction, and <code>clause(Head, Body)</code> unifies with clauses in the database of the form <code>Head :- Body</code>. Since Prolog programs are themselves sequences of Prolog terms (<code>:-/2</code> is an infix <a href="/wiki/Operator_(programming)" class="mw-redirect" title="Operator (programming)">operator</a>) that are easily read and inspected using built-in mechanisms (like <code>read/1</code>), it is possible to write customized interpreters that augment Prolog with domain-specific features. For example, Sterling and Shapiro present a meta-interpreter that performs reasoning with uncertainty, reproduced here with slight modifications:<a href="#cite_note-AOP94-31">[30]</a>: 330  <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>solve(true, 1) :- !. solve((Subgoal1,Subgoal2), Certainty) :- !, solve(Subgoal1, Certainty1), solve(Subgoal2, Certainty2), Certainty is min(Certainty1, Certainty2). solve(Goal, 1) :- builtin(Goal), !, Goal. solve(Head, Certainty) :- clause_cf(Head, Body, Certainty1), solve(Body, Certainty2), Certainty is Certainty1 * Certainty2. </pre></div> This interpreter uses a table of built-in Prolog predicates of the form<a href="#cite_note-AOP94-31">[30]</a>: 327  <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>builtin(A is B). builtin(read(X)). % etc. </pre></div> and clauses represented as <code>clause_cf(Head, Body, Certainty)</code>. Given those, it can be called as <code>solve(Goal, Certainty)</code> to execute <code>Goal</code> and obtain a measure of certainty about the result. <div class="mw-heading mw-heading2"><h2 id="Turing_completeness">Turing completeness</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=17" title="Edit section: Turing completeness">edit</a>]</div> Pure Prolog is based on a subset of first-order <a href="/wiki/Predicate_logic" class="mw-redirect" title="Predicate logic">predicate logic</a>, <a href="/wiki/Horn_clause" title="Horn clause">Horn clauses</a>, which is <a href="/wiki/Turing_completeness" title="Turing completeness">Turing-complete</a>. Turing completeness of Prolog can be shown by using it to simulate a Turing machine: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>turing(Tape0, Tape) :- perform(q0, [], Ls, Tape0, Rs), reverse(Ls, Ls1), append(Ls1, Rs, Tape). perform(qf, Ls, Ls, Rs, Rs) :- !. perform(Q0, Ls0, Ls, Rs0, Rs) :- symbol(Rs0, Sym, RsRest), once(rule(Q0, Sym, Q1, NewSym, Action)), action(Action, Ls0, Ls1, [NewSym|RsRest], Rs1), perform(Q1, Ls1, Ls, Rs1, Rs). symbol([], b, []). symbol([Sym|Rs], Sym, Rs). action(left, Ls0, Ls, Rs0, Rs) :- left(Ls0, Ls, Rs0, Rs). action(stay, Ls, Ls, Rs, Rs). action(right, Ls0, [Sym|Ls0], [Sym|Rs], Rs). left([], [], Rs0, [b|Rs0]). left([L|Ls], Ls, Rs, [L|Rs]). </pre></div> A simple example Turing machine is specified by the facts: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>rule(q0, 1, q0, 1, right). rule(q0, b, qf, 1, stay). </pre></div> This machine performs incrementation by one of a number in unary encoding: It loops over any number of "1" cells and appends an additional "1" at the end. Example query and result: <div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre>?- turing([1,1,1], Ts). Ts = [1, 1, 1, 1] ; </pre></div> This illustrates how any computation can be expressed declaratively as a sequence of state transitions, implemented in Prolog as a relation between successive states of interest. <div class="mw-heading mw-heading2"><h2 id="Implementation">Implementation</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=18" title="Edit section: Implementation">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Comparison_of_Prolog_implementations" title="Comparison of Prolog implementations">Comparison of Prolog implementations</a></div> <div class="mw-heading mw-heading3"><h3 id="ISO_Prolog">ISO Prolog</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=19" title="Edit section: ISO Prolog">edit</a>]</div> The <a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">International Organization for Standardization</a> (ISO) Prolog <a href="/wiki/Technical_standard" title="Technical standard">technical standard</a> consists of two parts. ISO/IEC 13211-1,<a href="#cite_note-ISO_13211-24">[23]</a><a href="#cite_note-32">[31]</a> published in 1995, aims to standardize the existing practices of the many implementations of the core elements of Prolog. It has clarified aspects of the language that were previously ambiguous and leads to portable programs. There are three corrigenda: Cor.1:2007,<a href="#cite_note-Cor.1-33">[32]</a> Cor.2:2012,<a href="#cite_note-Cor.2-34">[33]</a> and Cor.3:2017.<a href="#cite_note-Cor.3-35">[34]</a> ISO/IEC 13211-2,<a href="#cite_note-ISO_13211-24">[23]</a> published in 2000, adds support for modules to the standard. The standard is maintained by the <a href="/wiki/JTC1" class="mw-redirect" title="JTC1">ISO/IEC JTC1</a>/<a href="/wiki/SC22" class="mw-redirect" title="SC22">SC22</a>/WG17<a href="#cite_note-WG17-36">[35]</a> working group. ANSI X3J17 is the US Technical Advisory Group for the standard.<a href="#cite_note-X3J17-37">[36]</a> <div class="mw-heading mw-heading3"><h3 id="Compilation">Compilation</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=20" title="Edit section: Compilation">edit</a>]</div> For efficiency, Prolog code is typically compiled to abstract machine code, often influenced by the register-based <a href="/wiki/Warren_Abstract_Machine" title="Warren Abstract Machine">Warren Abstract Machine</a> (WAM) instruction set.<a href="#cite_note-38">[37]</a> Some implementations employ <a href="/wiki/Abstract_interpretation" title="Abstract interpretation">abstract interpretation</a> to derive type and mode information of predicates at compile time, or compile to real machine code for high performance.<a href="#cite_note-39">[38]</a> Devising efficient implementation methods for Prolog code is a field of active research in the logic programming community, and various other execution methods are employed in some implementations. These include <a href="/w/index.php?title=Clause_binarization&action=edit&redlink=1" class="new" title="Clause binarization (page does not exist)">clause binarization</a> and <a href="/wiki/Stack_machines" class="mw-redirect" title="Stack machines">stack-based virtual machines</a>.[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] <div class="mw-heading mw-heading3"><h3 id="Tail_recursion">Tail recursion</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=21" title="Edit section: Tail recursion">edit</a>]</div> Prolog systems typically implement a well-known optimization method called <a href="/wiki/Tail_call#Tail_call_optimization" title="Tail call">tail call optimization</a> (TCO) for deterministic predicates exhibiting <a href="/wiki/Tail_recursion" class="mw-redirect" title="Tail recursion">tail recursion</a> or, more generally, tail calls: A clause's stack frame is discarded before performing a call in a tail position. Therefore, deterministic tail-recursive predicates are executed with constant stack space, like loops in other languages. <div class="mw-heading mw-heading3"><h3 id="Term_indexing">Term indexing</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=22" title="Edit section: Term indexing">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Term_indexing" title="Term indexing">Term indexing</a></div> Finding clauses that are unifiable with a term in a query is linear in the number of clauses. <a href="/wiki/Term_indexing" title="Term indexing">Term indexing</a> uses a <a href="/wiki/Data_structure" title="Data structure">data structure</a> that enables <a href="/wiki/Sublinear_time" class="mw-redirect" title="Sublinear time">sub-linear-time</a> lookups.<a href="#cite_note-40">[39]</a> Indexing only affects program performance, it does not affect semantics. Most Prologs only use indexing on the first term, as indexing on all terms is expensive, but techniques based on field-encoded words or <a href="/wiki/Superimposed_code" title="Superimposed code">superimposed</a> codewords provide fast indexing across the full query and head.<a href="#cite_note-WisePowers-41">[40]</a><a href="#cite_note-Colomb-42">[41]</a> <div class="mw-heading mw-heading3"><h3 id="Hashing">Hashing</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=23" title="Edit section: Hashing">edit</a>]</div> Some Prolog systems, such as <a href="/wiki/Logic_Programming_Associates" title="Logic Programming Associates">WIN-PROLOG</a> and SWI-Prolog, now implement hashing to help handle large datasets more efficiently. This tends to yield very large performance gains when working with large corpora such as <a href="/wiki/WordNet" title="WordNet">WordNet</a>. <div class="mw-heading mw-heading3"><h3 id="Tabling">Tabling</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=24" title="Edit section: Tabling">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Tabled_logic_programming" title="Tabled logic programming">Tabled logic programming</a></div> Some Prolog systems, (<a href="/wiki/B-Prolog" title="B-Prolog">B-Prolog</a>, <a href="/wiki/XSB" title="XSB">XSB</a>, <a href="/wiki/SWI-Prolog" title="SWI-Prolog">SWI-Prolog</a>, <a href="/wiki/YAP_(Prolog)" title="YAP (Prolog)">YAP</a>, and <a href="/wiki/Ciao_(programming_language)" title="Ciao (programming language)">Ciao</a>), implement a <a href="/wiki/Memoization" title="Memoization">memoization</a> method called tabling, which frees the user from manually storing intermediate results. Tabling is a <a href="/wiki/Space%E2%80%93time_tradeoff" title="Space–time tradeoff">space–time tradeoff</a>; execution time can be reduced by using more memory to store intermediate results:<a href="#cite_note-43">[42]</a><a href="#cite_note-44">[43]</a> <blockquote>Subgoals encountered in a query evaluation are maintained in a table, along with answers to these subgoals. If a subgoal is re-encountered, the evaluation reuses information from the table rather than re-performing resolution against program clauses.<a href="#cite_note-45">[44]</a></blockquote> Tabling can be extended in various directions. It can support recursive predicates through SLG resolution or linear tabling. In a multi-threaded Prolog system tabling results could be kept private to a thread or shared among all threads. And in incremental tabling, tabling might react to changes. <div class="mw-heading mw-heading3"><h3 id="Implementation_in_hardware">Implementation in hardware</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=25" title="Edit section: Implementation in hardware">edit</a>]</div> During the <a href="/wiki/Fifth_Generation_Computer_Systems_project" class="mw-redirect" title="Fifth Generation Computer Systems project">Fifth Generation Computer Systems project</a>, there were attempts to implement Prolog in hardware with the aim of achieving faster execution with dedicated architectures.<a href="#cite_note-46">[45]</a><a href="#cite_note-47">[46]</a><a href="#cite_note-48">[47]</a> Furthermore, Prolog has a number of properties that may allow speed-up through parallel execution.<a href="#cite_note-49">[48]</a> A more recent approach has been to compile restricted Prolog programs to a <a href="/wiki/Field_programmable_gate_array" class="mw-redirect" title="Field programmable gate array">field programmable gate array</a>.<a href="#cite_note-50">[49]</a> However, rapid progress in general-purpose hardware has consistently overtaken more specialised architectures. In 1982, computers operated at around 10,000 to 100,000 LIPS [logical inferences per second]. The FGCS planned to produce computers operating at 0.1 to 1 GLIPS.<a href="#cite_note-51">[50]</a> The Institute for New Generation Computer Technology documents estimated that 1 LIP took about 100 operations on a conventional computer. The plan was to produce at the end of the project (in 1992) a machine with 1000 processors achieving 1 GLIPS, implying at least 1 MLIPS per processor.<a href="#cite_note-52">[51]</a> <a href="/wiki/Sega" title="Sega">Sega</a> implemented Prolog for use with the Sega AI Computer, released for the Japanese market in 1986. Prolog was used for reading <a href="/wiki/Natural_language" title="Natural language">natural language</a> inputs, in the <a href="/wiki/Japanese_language" title="Japanese language">Japanese language</a>, via a <a href="/wiki/Touch_pad" class="mw-redirect" title="Touch pad">touch pad</a>.<a href="#cite_note-53">[52]</a> <div class="mw-heading mw-heading2"><h2 id="Limits">Limits</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=26" title="Edit section: Limits">edit</a>]</div> Although Prolog is widely used in research and education,<a href="#cite_note-54">[53]</a> Prolog and other logic programming languages have not had a significant impact on the computer industry in general.<a href="#cite_note-RealWorld-55">[54]</a> Most applications are small by industrial standards, with few exceeding 100,000 lines of code.<a href="#cite_note-RealWorld-55">[54]</a><a href="#cite_note-The_Prolog_1000_database-56">[55]</a> <a href="/wiki/Programming_in_the_large" class="mw-redirect" title="Programming in the large">Programming in the large</a> is considered to be complex because not all Prolog compilers support modules, and there are compatibility problems between the module systems of the major Prolog compilers.<a href="#cite_note-cs.kuleuven.ac.be-27">[26]</a> Portability of Prolog code across implementations has also been a problem, but developments since 2007 have meant: "the portability within the family of Edinburgh/Quintus derived Prolog implementations is good enough to allow for maintaining portable real-world applications."<a href="#cite_note-57">[56]</a> Software developed in Prolog has been criticised for having a high performance penalty compared to conventional programming languages. In particular, Prolog's non-deterministic evaluation strategy can be problematic when programming deterministic computations, or when even using "don't care non-determinism" (where a single choice is made instead of backtracking over all possibilities). Cuts and other language constructs may have to be used to achieve desirable performance, destroying one of Prolog's main attractions, the ability to run programs "backwards and forwards".<a href="#cite_note-rethinking-58">[57]</a> Prolog is not purely declarative: because of constructs like the <a href="/wiki/Cut_(logic_programming)" title="Cut (logic programming)">cut operator</a>, a procedural reading of a Prolog program is needed to understand it.<a href="#cite_note-59">[58]</a> The order of clauses in a Prolog program is significant, as the execution strategy of the language depends on it.<a href="#cite_note-60">[59]</a> Other logic programming languages, such as <a href="/wiki/Datalog" title="Datalog">Datalog</a>, are truly declarative but restrict the language. As a result, many practical Prolog programs are written to conform to Prolog's <a href="/wiki/Depth-first_search" title="Depth-first search">depth-first search</a> order, rather than as purely declarative logic programs.<a href="#cite_note-rethinking-58">[57]</a> <div class="mw-heading mw-heading2"><h2 id="Extensions">Extensions</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=27" title="Edit section: Extensions">edit</a>]</div> Various implementations have been developed from Prolog to extend logic programming abilities in many directions. These include <a href="/wiki/Type_system" title="Type system">types</a>, modes, <a href="/wiki/Constraint_logic_programming" title="Constraint logic programming">constraint logic programming</a> (CLP), <a href="/wiki/Object-oriented_programming" title="Object-oriented programming">object-oriented</a> logic programming (OOLP), concurrency, <a href="/wiki/Linear_logic" title="Linear logic">linear logic</a> (LLP), functional and <a href="/wiki/Higher-order_logic" title="Higher-order logic">higher-order logic</a> programming abilities, plus interoperability with <a href="/wiki/Knowledge_base" title="Knowledge base">knowledge bases</a>: <div class="mw-heading mw-heading3"><h3 id="Types">Types</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=28" title="Edit section: Types">edit</a>]</div> Prolog is an untyped language. Attempts to introduce and extend Prolog with types began in the 1980s,<a href="#cite_note-61">[60]</a><a href="#cite_note-62">[61]</a> and continue as of 2008<a class="external text" href="https://en.wikipedia.org/w/index.php?title=Prolog&action=edit">[update]</a>.<a href="#cite_note-63">[62]</a> Type information is useful not only for <a href="/wiki/Type_safety" title="Type safety">type safety</a> but also for reasoning about Prolog programs.<a href="#cite_note-cite_doi|10.1007/BF01213601-64">[63]</a> <div class="mw-heading mw-heading3"><h3 id="Modes">Modes</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=29" title="Edit section: Modes">edit</a>]</div> <table style="float: right;" class="wikitable" border="1"> <tbody><tr> <th>Mode specifier </th> <th>Interpretation </th></tr> <tr> <td><code>+</code> </td> <td><code>nonvar</code> on entry </td></tr> <tr> <td><code>-</code> </td> <td><code>var</code> on entry </td></tr> <tr> <td><code>?</code> </td> <td>Not specified </td></tr></tbody></table> The syntax of Prolog does not specify which arguments of a predicate are inputs and which are outputs.<a href="#cite_note-craft-65">[64]</a> However, this information is significant and it is recommended that it be included in the comments.<a href="#cite_note-66">[65]</a> Modes provide valuable information when reasoning about Prolog programs<a href="#cite_note-cite_doi|10.1007/BF01213601-64">[63]</a> and can also be used to accelerate execution.<a href="#cite_note-67">[66]</a> <div class="mw-heading mw-heading3"><h3 id="Constraints">Constraints</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=30" title="Edit section: Constraints">edit</a>]</div> <a href="/wiki/Constraint_logic_programming" title="Constraint logic programming">Constraint logic programming</a> extends Prolog to include concepts from <a href="/wiki/Constraint_satisfaction" title="Constraint satisfaction">constraint satisfaction</a>.<a href="#cite_note-68">[67]</a><a href="#cite_note-69">[68]</a> A constraint logic program allows constraints in the body of clauses, such as: <code>A(X,Y) :- X+Y>0.</code> It is suited to large-scale <a href="/wiki/Combinatorial_optimisation" class="mw-redirect" title="Combinatorial optimisation">combinatorial optimisation</a> problems<a href="#cite_note-70">[69]</a> and is thus useful for applications in industrial settings, such as automated time-tabling and <a href="/wiki/Production_scheduling" class="mw-redirect" title="Production scheduling">production scheduling</a>. Most Prolog systems ship with at least one constraint solver for finite domains, and often also with solvers for other domains like <a href="/wiki/Rational_number" title="Rational number">rational numbers</a>. <div class="mw-heading mw-heading3"><h3 id="Object-orientation">Object-orientation</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=31" title="Edit section: Object-orientation">edit</a>]</div> <a href="/wiki/Flora-2" title="Flora-2">Flora-2</a> is an object-oriented knowledge representation and reasoning system based on <a href="/wiki/F-logic" title="F-logic">F-logic</a> and incorporates <a href="/wiki/HiLog" title="HiLog">HiLog</a>, <a href="/wiki/Transaction_logic" title="Transaction logic">Transaction logic</a>, and <a href="/wiki/Defeasible_reasoning" title="Defeasible reasoning">defeasible reasoning</a>. <a href="/wiki/Logtalk" title="Logtalk">Logtalk</a> is an object-oriented logic programming language that can use most Prolog implementations as a back-end compiler. As a multi-paradigm language, it includes support for both prototypes and classes. <a href="/w/index.php?title=Oblog&action=edit&redlink=1" class="new" title="Oblog (page does not exist)">Oblog</a> is a small, portable, object-oriented extension to Prolog by Margaret McDougall of EdCAAD, University of Edinburgh. <a href="/wiki/Objlog" title="Objlog">Objlog</a> was a frame-based language combining objects and Prolog II from CNRS, Marseille, France. <a href="/wiki/Prolog%2B%2B" title="Prolog++">Prolog++</a> was developed by <a href="/wiki/Logic_Programming_Associates" title="Logic Programming Associates">Logic Programming Associates</a> and first released in 1989 for MS-DOS PCs. Support for other platforms was added, and a second version was released in 1995. A book about Prolog++ by Chris Moss was published by Addison-Wesley in 1994. <a href="/wiki/Visual_Prolog" title="Visual Prolog">Visual Prolog</a> is a multi-paradigm language with interfaces, classes, implementations and object expressions. <div class="mw-heading mw-heading3"><h3 id="Graphics">Graphics</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=32" title="Edit section: Graphics">edit</a>]</div> Prolog systems that provide a <a href="/wiki/Graphics_library" title="Graphics library">graphics library</a> are <a href="/wiki/SWI-Prolog" title="SWI-Prolog">SWI-Prolog</a>,<a href="#cite_note-71">[70]</a> <a href="/wiki/Visual_Prolog" title="Visual Prolog">Visual Prolog</a>, <a href="/wiki/Logic_Programming_Associates" title="Logic Programming Associates">WIN-PROLOG</a>, and <a href="/wiki/B-Prolog" title="B-Prolog">B-Prolog</a>. <div class="mw-heading mw-heading3"><h3 id="Concurrency">Concurrency</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=33" title="Edit section: Concurrency">edit</a>]</div> Prolog-MPI is an open-source <a href="/wiki/SWI-Prolog" title="SWI-Prolog">SWI-Prolog</a> extension for <a href="/wiki/Distributed_computing" title="Distributed computing">distributed computing</a> over the <a href="/wiki/Message_Passing_Interface" title="Message Passing Interface">Message Passing Interface</a>.<a href="#cite_note-72">[71]</a> Also there are various concurrent Prolog programming languages.<a href="#cite_note-73">[72]</a> <div class="mw-heading mw-heading3"><h3 id="Web_programming">Web programming</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=34" title="Edit section: Web programming">edit</a>]</div> Some Prolog implementations, notably <a href="/wiki/Visual_Prolog" title="Visual Prolog">Visual Prolog</a>, <a href="/wiki/SWI-Prolog" title="SWI-Prolog">SWI-Prolog</a> and <a href="/wiki/Ciao_(programming_language)" title="Ciao (programming language)">Ciao</a>, support <a href="/wiki/Server-side" class="mw-redirect" title="Server-side">server-side</a> <a href="/wiki/Web_programming" class="mw-redirect" title="Web programming">web programming</a> with support for web protocols, <a href="/wiki/HTML" title="HTML">HTML</a> and <a href="/wiki/XML" title="XML">XML</a>.<a href="#cite_note-74">[73]</a> There are also extensions to support <a href="/wiki/Semantic_web" class="mw-redirect" title="Semantic web">semantic web</a> formats such as <a href="/wiki/Resource_Description_Framework" title="Resource Description Framework">Resource Description Framework</a> (RDF) and <a href="/wiki/Web_Ontology_Language" title="Web Ontology Language">Web Ontology Language</a> (OWL).<a href="#cite_note-75">[74]</a><a href="#cite_note-76">[75]</a> Prolog has also been suggested as a <a href="/wiki/Client-side" class="mw-redirect" title="Client-side">client-side</a> language.<a href="#cite_note-77">[76]</a> In addition, Visual Prolog supports <a href="/wiki/JSON-RPC" title="JSON-RPC">JSON-RPC</a> and <a href="/wiki/Websockets" class="mw-redirect" title="Websockets">Websockets</a>. <div class="mw-heading mw-heading3"><h3 id="Adobe_Flash">Adobe Flash</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=35" title="Edit section: Adobe Flash">edit</a>]</div> <a rel="nofollow" class="external text" href="https://sites.google.com/site/cedarprolog/">Cedar</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20101019074143/http://sites.google.com/site/cedarprolog/">Archived</a> 2010-10-19 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> is a free and basic Prolog interpreter. From version 4 and above Cedar has a FCA (Flash Cedar App) support. This provides a new platform to programming in Prolog through <a href="/wiki/ActionScript" title="ActionScript">ActionScript</a>. <div class="mw-heading mw-heading3"><h3 id="Other">Other</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=36" title="Edit section: Other">edit</a>]</div> <ul><li><a href="/wiki/F-logic" title="F-logic">F-logic</a> extends Prolog with frames/objects for <a href="/wiki/Knowledge_representation" class="mw-redirect" title="Knowledge representation">knowledge representation</a>.</li> <li><a href="/wiki/Transaction_logic" title="Transaction logic">Transaction logic</a> extends Prolog with a logical theory of state-changing update operators. It has both a model-theoretic and procedural semantics.</li> <li><a href="/w/index.php?title=OW_Prolog&action=edit&redlink=1" class="new" title="OW Prolog (page does not exist)">OW Prolog</a> has been created in order to answer Prolog's lack of graphics and interface.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Interfaces_to_other_languages">Interfaces to other languages</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=37" title="Edit section: Interfaces to other languages">edit</a>]</div> Frameworks exist which can bridge between Prolog and other languages: <ul><li>The <a rel="nofollow" class="external text" href="https://www.lpa.co.uk/int.htm">LPA Intelligence Server</a> allows embedding <a rel="nofollow" class="external text" href="https://www.lpa.co.uk/win.htm">LPA Prolog for Windows</a> in other programming languages, including: <a href="/wiki/C_(programming_language)" title="C (programming language)">C</a>, <a href="/wiki/C%2B%2B" title="C++">C++</a>, <a href="/wiki/C_Sharp_(programming_language)" title="C Sharp (programming language)">C#</a>, <a href="/wiki/Java_(programming_language)" title="Java (programming language)">Java</a>, <a href="/wiki/Visual_Basic_(classic)" title="Visual Basic (classic)">Visual Basic</a> (VB), <a href="/wiki/Delphi_(software)" title="Delphi (software)">Delphi</a>, <a href="/wiki/.NET" title=".NET">.NET</a>, <a href="/wiki/Lua_(programming_language)" title="Lua (programming language)">Lua</a>, <a href="/wiki/Python_(programming_language)" title="Python (programming language)">Python</a>, and others. It exploits the dedicated string data type which LPA Prolog provides</li> <li>The <a rel="nofollow" class="external text" href="http://www.amzi.com/#apls">Logic Server</a> Application Programming Interface (<a href="/wiki/API" title="API">API</a>) allows both the extension and embedding of Prolog in <a href="/wiki/C_(programming_language)" title="C (programming language)">C</a>, <a href="/wiki/C%2B%2B" title="C++">C++</a>, <a href="/wiki/Java_(programming_language)" title="Java (programming language)">Java</a>, <a href="/wiki/Visual_Basic_(classic)" title="Visual Basic (classic)">Visual Basic</a> (VB), <a href="/wiki/Delphi_(software)" title="Delphi (software)">Delphi</a>, <a href="/wiki/.NET" title=".NET">.NET</a>, and any language or environment which can call a .dll or .so. It is implemented for <a rel="nofollow" class="external text" href="http://www.amzi.com/#apls">Amzi! Prolog + Logic Server</a> but the API specification can be made available for any implementation.</li> <li><a rel="nofollow" class="external text" href="https://jpl7.org/">JPL</a> is a bi-directional Java Prolog bridge which ships with SWI-Prolog by default, allowing Java and Prolog to call each other (recursively). It is known to have good concurrency support and is under active development.</li> <li><a rel="nofollow" class="external text" href="http://interprolog.com/">InterProlog</a>, a programming <a href="/wiki/Library_(computing)" title="Library (computing)">library</a> bridge between <a href="/wiki/Java_platform" class="mw-redirect" title="Java platform">Java</a> and Prolog, implementing bi-directional predicate/method calling between both languages. Java objects can be mapped into Prolog terms and vice versa. Allows the development of <a href="/wiki/Graphical_user_interface" title="Graphical user interface">graphical user interfaces</a> (GUIs) and other functions in Java while leaving logic processing in the Prolog layer. Supports <a href="/wiki/XSB" title="XSB">XSB</a> and <a href="/wiki/SWI-Prolog" title="SWI-Prolog">SWI-Prolog</a>.</li> <li><a href="/wiki/Prova" title="Prova">Prova</a> provides native syntax integration with Java, agent messaging and reaction rules. Prova positions itself as a rule-based scripting (RBS) system for middleware. The language breaks new ground in combining <a href="/wiki/Imperative_programming" title="Imperative programming">imperative</a> and <a href="/wiki/Declarative_programming" title="Declarative programming">declarative programming</a>.</li> <li><a rel="nofollow" class="external text" href="https://github.com/raydac/jprol/">PROL</a> An embeddable Prolog engine for Java. It includes a small IDE and a few libraries.</li> <li><a rel="nofollow" class="external text" href="https://www.gnu.org/software/gnuprologjava/">GNU Prolog for Java</a> is an implementation of ISO Prolog as a Java library (gnu.prolog)</li> <li><a href="/wiki/Ciao_(programming_language)" title="Ciao (programming language)">Ciao</a> provides interfaces to C, C++, Java, and relational databases.</li> <li><a rel="nofollow" class="external text" href="http://sourceforge.net/projects/cs-prolog/">C#-Prolog</a> is a Prolog interpreter written in (managed) C#. Can easily be integrated in C# programs. Characteristics: reliable and fairly fast interpreter, command line interface, Windows-interface, builtin DCG, XML-predicates, SQL-predicates, extendible. The complete source code is available, including a parser generator that can be used for adding special purpose extensions.</li> <li><a rel="nofollow" class="external text" href="https://github.com/Trismegiste/WamBundle">A Warren Abstract Machine for PHP</a> A Prolog compiler and interpreter in PHP 5.3. A library that can be used standalone or within Symfony2.1 framework which was translated from <a rel="nofollow" class="external text" href="http://stefan.buettcher.org/">Stephan Buettcher's</a> work in Java which can be found [here <a rel="nofollow" class="external text" href="http://stefan.buettcher.org/cs/wam/">stefan.buettcher.org/cs/wam/</a>]</li> <li><a rel="nofollow" class="external text" href="http://tuprolog.unibo.it">tuProlog</a> is a lightweight Prolog system for distributed applications and infrastructures, intentionally designed around a minimal core, to be either statically or dynamically configured by loading/unloading libraries of predicates. tuProlog natively supports multi-paradigm programming, providing a clean, seamless integration model between Prolog and mainstream object-oriented languages, namely Java, for tuProlog Java version, and any .NET-based language (C#, F#..), for tuProlog .NET version.</li> <li><a rel="nofollow" class="external text" href="https://www.swi-prolog.org/pldoc/doc_for?object=section(%27packages/janus.html%27)">Janus</a> is a bi-directional interface between Prolog and Python using portable low-level primitives. It was initially developed for XSB by Anderson and Swift,<a href="#cite_note-78">[77]</a> but has been adopted as a joint initiative by the XSB, Ciao and SWI-Prolog teams.</li></ul> <div class="mw-heading mw-heading2"><h2 id="History">History</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=38" title="Edit section: History">edit</a>]</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Early_Prolog_timeline.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/49/Early_Prolog_timeline.svg/440px-Early_Prolog_timeline.svg.png" decoding="async" width="440" height="176" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/49/Early_Prolog_timeline.svg/660px-Early_Prolog_timeline.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/49/Early_Prolog_timeline.svg/880px-Early_Prolog_timeline.svg.png 2x" data-file-width="600" data-file-height="240" /></a><figcaption>Timeline of early developments in Prolog</figcaption></figure> The name Prolog was chosen by Philippe Roussel, at the suggestion of his wife, as an abbreviation for programmation en logique (<a href="/wiki/French_language" title="French language">French</a> for programming in <a href="/wiki/Logic" title="Logic">logic</a>).<a href="#cite_note-79">[78]</a> It was created around 1972 by <a href="/wiki/Alain_Colmerauer" title="Alain Colmerauer">Alain Colmerauer</a> with Philippe Roussel, based on <a href="/wiki/Robert_Kowalski" title="Robert Kowalski">Robert Kowalski</a>'s procedural interpretation of <a href="/wiki/Horn_clause" title="Horn clause">Horn clauses</a>. It was motivated in part by the desire to reconcile the use of logic as a declarative knowledge representation language with the procedural representation of knowledge that was popular in North America in the late 1960s and early 1970s. According to <a href="/wiki/Robert_Kowalski" title="Robert Kowalski">Robert Kowalski</a>, the first Prolog system was developed in 1972 by Colmerauer and Phillipe Roussel.<a href="#cite_note-Kowalski-80">[79]</a><a href="#cite_note-81">[80]</a><a href="#cite_note-82">[81]</a> The first implementation of Prolog was an interpreter written in <a href="/wiki/Fortran" title="Fortran">Fortran</a> by Gerard Battani and Henri Meloni. <a href="/wiki/David_H._D._Warren" title="David H. D. Warren">David H. D. Warren</a> took this interpreter to the <a href="/wiki/University_of_Edinburgh" title="University of Edinburgh">University of Edinburgh</a>, and there implemented an alternative front-end, which came to define the "Edinburgh Prolog" syntax used by most modern implementations. Warren also implemented the first compiler for Prolog, creating the influential DEC-10 Prolog in collaboration with Fernando Pereira. Warren later generalised the ideas behind DEC-10 Prolog, to create the <a href="/wiki/Warren_Abstract_Machine" title="Warren Abstract Machine">Warren Abstract Machine</a>. European AI researchers favored Prolog while Americans favored <a href="/wiki/Lisp_(programming_language)" title="Lisp (programming language)">Lisp</a>, reportedly causing many nationalistic debates on the merits of the languages.<a href="#cite_note-pountain198410-83">[82]</a> Much of the modern development of Prolog came from the impetus of the <a href="/wiki/Fifth_Generation_Computer_Systems_project" class="mw-redirect" title="Fifth Generation Computer Systems project">Fifth Generation Computer Systems project</a> (FGCS), which developed a variant of Prolog named <a href="/wiki/KL1" title="KL1">Kernel Language</a> for its first <a href="/wiki/Operating_system" title="Operating system">operating system</a>. Pure Prolog was originally restricted to the use of a <a href="/wiki/Resolution_(logic)" title="Resolution (logic)">resolution</a> theorem prover with <a href="/wiki/Horn_clause" title="Horn clause">Horn clauses</a> of the form: <pre>H :- B1, ..., Bn. </pre> The application of the theorem-prover treats such clauses as procedures: <pre>to show/solve H, show/solve B1 and ... and Bn. </pre> Pure Prolog was soon extended, however, to include <a href="/wiki/Negation_as_failure" title="Negation as failure">negation as failure</a>, in which negative conditions of the form not(Bi) are shown by trying and failing to solve the corresponding positive conditions Bi. Subsequent extensions of Prolog by the original team introduced <a href="/wiki/Constraint_logic_programming" title="Constraint logic programming">constraint logic programming</a> abilities into the implementations. <div class="mw-heading mw-heading2"><h2 id="Use_in_industry">Use in industry</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=39" title="Edit section: Use in industry">edit</a>]</div> Prolog has been used in <a href="/wiki/Watson_(computer)" class="mw-redirect" title="Watson (computer)">Watson</a>. Watson uses IBM's DeepQA software and the Apache <a href="/wiki/UIMA" title="UIMA">UIMA</a> (Unstructured Information Management Architecture) framework. The system was written in various languages, including Java, C++, and Prolog, and runs on the <a href="/wiki/SUSE_Linux_Enterprise_Server" class="mw-redirect" title="SUSE Linux Enterprise Server">SUSE Linux Enterprise Server</a> 11 operating system using <a href="/wiki/Apache_Hadoop" title="Apache Hadoop">Apache Hadoop</a> framework to provide distributed computing. Prolog is used for <a href="/wiki/Pattern_matching" title="Pattern matching">pattern matching</a> over natural language parse trees. The developers have stated: "We required a language in which we could conveniently express pattern matching rules over the parse trees and other annotations (such as named entity recognition results), and a technology that could execute these rules very efficiently. We found that Prolog was the ideal choice for the language due to its simplicity and <a href="/wiki/Expressive_power_(computer_science)" title="Expressive power (computer science)">expressiveness</a>."<a href="#cite_note-lally-12">[12]</a> Prolog is being used in the Low-Code Development Platform <a href="/wiki/GeneXus" title="GeneXus">GeneXus</a>, which is focused around AI.[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] Open source <a href="/wiki/Graph_database" title="Graph database">graph database</a> <a href="/wiki/TerminusDB" title="TerminusDB">TerminusDB</a> is implemented in Prolog.<a href="#cite_note-84">[83]</a> TerminusDB is designed for collaboratively building and curating <a href="/wiki/Knowledge_graph" title="Knowledge graph">knowledge graphs</a>. <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=40" title="Edit section: See also">edit</a>]</div> <ul><li><a href="/wiki/Comparison_of_Prolog_implementations" title="Comparison of Prolog implementations">Comparison of Prolog implementations</a></li> <li><a href="/wiki/Logico-linguistic_modeling" title="Logico-linguistic modeling">Logico-linguistic modeling</a>. A method for building knowledge-based system that uses Prolog.</li> <li><a href="/wiki/Answer_set_programming" title="Answer set programming">Answer set programming</a>. A fully declarative approach to logic programming.</li> <li><a href="/wiki/Association_for_Logic_Programming" title="Association for Logic Programming">Association for Logic Programming</a></li></ul> <div class="mw-heading mw-heading3"><h3 id="Related_languages">Related languages</h3>[<a href="/w/index.php?title=Prolog&action=edit&section=41" title="Edit section: Related languages">edit</a>]</div> <ul><li>The <a href="/wiki/G%C3%B6del_(programming_language)" title="Gödel (programming language)">Gödel</a> language is a strongly typed implementation of <a href="/wiki/Concurrent_constraint_logic_programming" title="Concurrent constraint logic programming">concurrent constraint logic programming</a>. It is built on <a href="/wiki/SICStus_Prolog" title="SICStus Prolog">SICStus Prolog</a>.</li> <li><a href="/wiki/Visual_Prolog" title="Visual Prolog">Visual Prolog</a>, formerly named PDC Prolog and Turbo Prolog, is a <a href="/wiki/Data_type" title="Data type">strongly typed</a> <a href="/wiki/Object-oriented_programming" title="Object-oriented programming">object-oriented</a> dialect of Prolog, which is very different from standard Prolog. As Turbo Prolog, it was marketed by Borland, but is now developed and marketed by the Danish firm Prolog Development Center (PDC) that originally produced it.</li> <li><a href="/wiki/Datalog" title="Datalog">Datalog</a> is a subset of Prolog. It is limited to relationships that may be stratified and does not allow compound terms. In contrast to Prolog, Datalog is not <a href="/wiki/Turing-complete" class="mw-redirect" title="Turing-complete">Turing-complete</a>.</li> <li><a href="/wiki/Mercury_(programming_language)" title="Mercury (programming language)">Mercury</a> is an offshoot of Prolog geared toward software engineering in the large with a static, polymorphic type system, as well as a mode and determinism system.</li> <li>GraphTalk is a proprietary implementation of Warren's Abstract Machine, with additional object-oriented properties.</li> <li>In some ways[<a href="/wiki/Wikipedia:Avoid_weasel_words" class="mw-redirect" title="Wikipedia:Avoid weasel words">which?</a>] Prolog is a subset of <a href="/wiki/Planner_(programming_language)" title="Planner (programming language)">Planner</a>. The ideas in Planner were later further developed in the <a href="/wiki/Scientific_Community_Metaphor" class="mw-redirect" title="Scientific Community Metaphor">Scientific Community Metaphor</a>.</li> <li><a href="/wiki/AgentSpeak" title="AgentSpeak">AgentSpeak</a> is a variant of Prolog for programming agent behavior in <a href="/wiki/Multi-agent_system" title="Multi-agent system">multi-agent systems</a>.</li> <li><a href="/wiki/Erlang_(programming_language)" title="Erlang (programming language)">Erlang</a> began life with a Prolog-based implementation and maintains much of Prolog's unification-based syntax.</li> <li><a rel="nofollow" class="external text" href="https://picolisp.com/wiki/?accessToLispFunctionFromPilog">Pilog</a> is a declarative language built on top of <a href="/wiki/PicoLisp" title="PicoLisp">PicoLisp</a>, that has the semantics of Prolog, but uses the syntax of Lisp.</li> <li><a href="/wiki/%CE%9BProlog" title="ΛProlog">λProlog</a> is an extension of core Prolog that features polymorphic typing, modular programming, and higher-order programming, including direct support for terms with variable-binding operators through so-called λ-tree syntax and higher-order pattern unification.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=42" title="Edit section: Notes">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-13"><a href="#cite_ref-13">^</a> The Prolog terminology differs from that of <a href="/wiki/First-order_logic" title="First-order logic">logic</a>. A term of Prolog is (depending on the context) a <a href="/wiki/Term_(logic)" title="Term (logic)">term</a> or an <a href="/wiki/Atomic_formula" title="Atomic formula">atomic formula</a> of logic. An atom in a standard logic terminology means an <a href="/wiki/Atomic_formula" title="Atomic formula">atomic formula</a>; an atom of Prolog (depending on the context) is a constant, function symbol or predicate symbol of logic. </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=43" title="Edit section: References">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-Clocksin2003-1"><a href="#cite_ref-Clocksin2003_1-0">^</a> <style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFClocksinMellish2003" class="citation book cs1">Clocksin, William F.; Mellish, Christopher S. (2003). Programming in Prolog. Berlin; New York: Springer-Verlag. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-540-00678-7" title="Special:BookSources/978-3-540-00678-7"><bdi>978-3-540-00678-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Programming+in+Prolog&rft.place=Berlin%3B+New+York&rft.pub=Springer-Verlag&rft.date=2003&rft.isbn=978-3-540-00678-7&rft.aulast=Clocksin&rft.aufirst=William+F.&rft.au=Mellish%2C+Christopher+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-Bratko2012-2"><a href="#cite_ref-Bratko2012_2-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBratko2012" class="citation book cs1">Bratko, Ivan (2012). Prolog programming for artificial intelligence (4th ed.). Harlow, England; New York: Addison Wesley. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-321-41746-6" title="Special:BookSources/978-0-321-41746-6"><bdi>978-0-321-41746-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Prolog+programming+for+artificial+intelligence&rft.place=Harlow%2C+England%3B+New+York&rft.edition=4th&rft.pub=Addison+Wesley&rft.date=2012&rft.isbn=978-0-321-41746-6&rft.aulast=Bratko&rft.aufirst=Ivan&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-Covington1994-3"><a href="#cite_ref-Covington1994_3-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCovington1994" class="citation book cs1">Covington, Michael A. (1994). Natural language processing for Prolog programmers. Englewood Cliffs, N.J.: Prentice Hall. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-13-629213-5" title="Special:BookSources/978-0-13-629213-5"><bdi>978-0-13-629213-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Natural+language+processing+for+Prolog+programmers&rft.place=Englewood+Cliffs%2C+N.J.&rft.pub=Prentice+Hall&rft.date=1994&rft.isbn=978-0-13-629213-5&rft.aulast=Covington&rft.aufirst=Michael+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-lloyd84-4">^ <a href="#cite_ref-lloyd84_4-0">a</a> <a href="#cite_ref-lloyd84_4-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLloyd,_J._W.1984" class="citation book cs1">Lloyd, J. W. (1984). Foundations of logic programming. Berlin: Springer-Verlag. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-540-13299-8" title="Special:BookSources/978-3-540-13299-8"><bdi>978-3-540-13299-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Foundations+of+logic+programming&rft.place=Berlin&rft.pub=Springer-Verlag&rft.date=1984&rft.isbn=978-3-540-13299-8&rft.au=Lloyd%2C+J.+W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-5"><a href="#cite_ref-5">^</a> See <a href="/wiki/Logic_programming#History" title="Logic programming">Logic programming § History</a>. </li> <li id="cite_note-6"><a href="#cite_ref-6">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStickel1988" class="citation journal cs1">Stickel, M. E. (1988). "A prolog technology theorem prover: Implementation by an extended prolog compiler". <a href="/wiki/Journal_of_Automated_Reasoning" title="Journal of Automated Reasoning">Journal of Automated Reasoning</a>. 4 (4): 353–380. <a href="/wiki/CiteSeerX_(identifier)" class="mw-redirect" title="CiteSeerX (identifier)">CiteSeerX</a> <a rel="nofollow" class="external text" href="https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.47.3057">10.1.1.47.3057</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2FBF00297245">10.1007/BF00297245</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:14621218">14621218</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Automated+Reasoning&rft.atitle=A+prolog+technology+theorem+prover%3A+Implementation+by+an+extended+prolog+compiler&rft.volume=4&rft.issue=4&rft.pages=353-380&rft.date=1988&rft_id=https%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fsummary%3Fdoi%3D10.1.1.47.3057%23id-name%3DCiteSeerX&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A14621218%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1007%2FBF00297245&rft.aulast=Stickel&rft.aufirst=M.+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-7"><a href="#cite_ref-7">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMerritt,_Dennis1989" class="citation book cs1">Merritt, Dennis (1989). <a rel="nofollow" class="external text" href="https://archive.org/details/buildingexpertsy0000merr">Building expert systems in Prolog</a>. Berlin: Springer-Verlag. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-387-97016-5" title="Special:BookSources/978-0-387-97016-5"><bdi>978-0-387-97016-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Building+expert+systems+in+Prolog&rft.place=Berlin&rft.pub=Springer-Verlag&rft.date=1989&rft.isbn=978-0-387-97016-5&rft.au=Merritt%2C+Dennis&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fbuildingexpertsy0000merr&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-8"><a href="#cite_ref-8">^</a> Felty, Amy. "A logic programming approach to implementing higher-order term rewriting." Extensions of Logic Programming (1992): 135-161. </li> <li id="cite_note-Lee2015-9"><a href="#cite_ref-Lee2015_9-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKent_D._Lee2015" class="citation book cs1">Kent D. Lee (19 January 2015). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=dERFBgAAQBAJ&q=prolog+type+inference&pg=PA298">Foundations of Programming Languages</a>. Springer. pp. 298–. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-319-13314-0" title="Special:BookSources/978-3-319-13314-0"><bdi>978-3-319-13314-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Foundations+of+Programming+Languages&rft.pages=298-&rft.pub=Springer&rft.date=2015-01-19&rft.isbn=978-3-319-13314-0&rft.au=Kent+D.+Lee&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DdERFBgAAQBAJ%26q%3Dprolog%2Btype%2Binference%26pg%3DPA298&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-Schmid2003-10"><a href="#cite_ref-Schmid2003_10-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFUte_Schmid2003" class="citation book cs1"><a href="/wiki/Ute_Schmid" title="Ute Schmid">Ute Schmid</a> (21 August 2003). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=p-Fy25LE4lMC">Inductive Synthesis of Functional Programs: Universal Planning, Folding of Finite Programs, and Schema Abstraction by Analogical Reasoning</a>. Springer Science & Business Media. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-540-40174-2" title="Special:BookSources/978-3-540-40174-2"><bdi>978-3-540-40174-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Inductive+Synthesis+of+Functional+Programs%3A+Universal+Planning%2C+Folding+of+Finite+Programs%2C+and+Schema+Abstraction+by+Analogical+Reasoning&rft.pub=Springer+Science+%26+Business+Media&rft.date=2003-08-21&rft.isbn=978-3-540-40174-2&rft.au=Ute+Schmid&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dp-Fy25LE4lMC&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-11"><a href="#cite_ref-11">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFernando_C._N._PereiraStuart_M._Shieber2005" class="citation book cs1"><a href="/wiki/Fernando_Pereira" title="Fernando Pereira">Fernando C. N. Pereira</a>; Stuart M. Shieber (2005). <a rel="nofollow" class="external text" href="http://mtome.com/Publications/PNLA/pnla.html">Prolog and Natural Language Analysis</a>. Microtome.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Prolog+and+Natural+Language+Analysis&rft.pub=Microtome&rft.date=2005&rft.au=Fernando+C.+N.+Pereira&rft.au=Stuart+M.+Shieber&rft_id=http%3A%2F%2Fmtome.com%2FPublications%2FPNLA%2Fpnla.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-lally-12">^ <a href="#cite_ref-lally_12-0">a</a> <a href="#cite_ref-lally_12-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAdam_LallyPaul_Fodor2011" class="citation web cs1">Adam Lally; Paul Fodor (31 March 2011). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20140903064037/http://www.cs.nmsu.edu/ALP/2011/03/natural-language-processing-with-prolog-in-the-ibm-watson-system/">"Natural Language Processing With Prolog in the IBM Watson System"</a>. Association for Logic Programming. Archived from <a rel="nofollow" class="external text" href="http://www.cs.nmsu.edu/ALP/2011/03/natural-language-processing-with-prolog-in-the-ibm-watson-system/">the original</a> on 3 September 2014. Retrieved 13 June 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Natural+Language+Processing+With+Prolog+in+the+IBM+Watson+System&rft.pub=Association+for+Logic+Programming&rft.date=2011-03-31&rft.au=Adam+Lally&rft.au=Paul+Fodor&rft_id=http%3A%2F%2Fwww.cs.nmsu.edu%2FALP%2F2011%2F03%2Fnatural-language-processing-with-prolog-in-the-ibm-watson-system%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> See also <a href="/wiki/Watson_(computer)" class="mw-redirect" title="Watson (computer)">Watson (computer)</a>. </li> <li id="cite_note-ISO_13211-1_6.3.7-14"><a href="#cite_ref-ISO_13211-1_6.3.7_14-0">^</a> ISO/IEC 13211-1:1995 Prolog, 6.3.7 Terms - double quoted list notation. <a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">International Organization for Standardization</a>, Geneva. </li> <li id="cite_note-15"><a href="#cite_ref-15">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCarlsson2014" class="citation book cs1">Carlsson, Mats (27 May 2014). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=dZimAwAAQBAJ&q=prolog%20failure%20driven%20loop%20%22iteration%22&pg=PA148">SICStus Prolog User's Manual 4.3: Core reference documentation</a>. 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Retrieved 23 October 2013.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Byte&rft.atitle=POP+and+SNAP&rft.pages=381&rft.date=1984-10&rft.aulast=Pountain&rft.aufirst=Dick&rft_id=https%3A%2F%2Farchive.org%2Fstream%2Fbyte-magazine-1984-10%2F1984_10_BYTE_09-11_Databases%23page%2Fn377%2Fmode%2F2up&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> <li id="cite_note-84"><a href="#cite_ref-84">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://github.com/terminusdb/terminusdb">terminusdb/terminusdb</a>, TerminusDB, 2020-12-13, retrieved 2020-12-15</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=terminusdb%2Fterminusdb&rft.pub=TerminusDB&rft.date=2020-12-13&rft_id=https%3A%2F%2Fgithub.com%2Fterminusdb%2Fterminusdb&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2>[<a href="/w/index.php?title=Prolog&action=edit&section=44" title="Edit section: Further reading">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin refbegin-columns references-column-width" style="column-width: 30em"> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBlackburnBosStriegnitz2006" class="citation book cs1">Blackburn, Patrick; Bos, Johan; Striegnitz, Kristina (2006). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20070826231318/http://www.learnprolognow.org/">Learn Prolog Now!</a>. College Publications. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-904987-17-8" title="Special:BookSources/978-1-904987-17-8"><bdi>978-1-904987-17-8</bdi></a>. Archived from <a rel="nofollow" class="external text" href="http://www.learnprolognow.org/">the original</a> on 2007-08-26. Retrieved 2008-12-02.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Learn+Prolog+Now%21&rft.pub=College+Publications&rft.date=2006&rft.isbn=978-1-904987-17-8&rft.aulast=Blackburn&rft.aufirst=Patrick&rft.au=Bos%2C+Johan&rft.au=Striegnitz%2C+Kristina&rft_id=http%3A%2F%2Fwww.learnprolognow.org%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProlog" class="Z3988"></li> <li><a href="/wiki/Ivan_Bratko_(computer_scientist)" title="Ivan Bratko (computer scientist)">Ivan Bratko</a>, Prolog Programming for Artificial Intelligence, 4th ed., 2012, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-321-41746-6" title="Special:BookSources/978-0-321-41746-6">978-0-321-41746-6</a>. <a rel="nofollow" class="external text" href="https://ailab.si/ivan/datoteke/dokumenti/32/107_19_Bratko_Prolog_book_web_resources.htm">Book supplements and source code</a>[<a href="/wiki/Wikipedia:Link_rot" title="Wikipedia:Link rot">permanent dead link</a>‍]</li> <li>William F. Clocksin, Christopher S. Mellish: Programming in Prolog: Using the ISO Standard. Springer, 5th ed., 2003, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-540-00678-7" title="Special:BookSources/978-3-540-00678-7">978-3-540-00678-7</a>. (This edition is updated for ISO Prolog. Prior editions described Edinburgh Prolog.)</li> <li>William F. Clocksin: Clause and Effect. Prolog Programming for the Working Programmer. Springer, 2003, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-540-62971-9" title="Special:BookSources/978-3-540-62971-9">978-3-540-62971-9</a>.</li> <li><a href="/w/index.php?title=Michael_A._Covington&action=edit&redlink=1" class="new" title="Michael A. Covington (page does not exist)">Michael A. Covington</a>, Donald Nute, Andre Vellino, Prolog Programming in Depth, 1996, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-13-138645-X" title="Special:BookSources/0-13-138645-X">0-13-138645-X</a>.</li> <li>Michael A. Covington, Natural Language Processing for Prolog Programmers, 1994, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-13-629213-5" title="Special:BookSources/978-0-13-629213-5">978-0-13-629213-5</a></li> <li>M. S. Dawe and C.M.Dawe, Prolog for Computer Sciences, Springer Verlag 1992.</li> <li>ISO/IEC 13211: Information technology – Programming languages – Prolog. <a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">International Organization for Standardization</a>, Geneva.</li> <li>Feliks Kluźniak and Stanisław Szpakowicz (with a contribution by Janusz S. Bień). Prolog for Programmers. Academic Press Inc. (London), 1985, 1987 (available under a <a href="/wiki/Creative_Commons" title="Creative Commons">Creative Commons</a> license at <a rel="nofollow" class="external text" href="https://sites.google.com/site/prologforprogrammers/">sites.google.com/site/prologforprogrammers/</a>[<a href="/wiki/Wikipedia:Link_rot" title="Wikipedia:Link rot">permanent dead link</a>‍]). <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-12-416521-4" title="Special:BookSources/0-12-416521-4">0-12-416521-4</a>.</li> <li><a href="/wiki/Richard_O%27Keefe" title="Richard O'Keefe">Richard O'Keefe</a>, The Craft of Prolog, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-262-15039-5" title="Special:BookSources/0-262-15039-5">0-262-15039-5</a>.</li> <li>Robert Smith, John Gibson, <a href="/wiki/Aaron_Sloman" title="Aaron Sloman">Aaron Sloman</a>: 'POPLOG's two-level virtual machine support for interactive languages', in Research Directions in Cognitive Science Volume 5: Artificial Intelligence, Eds <a href="/wiki/Derek_H._Sleeman" title="Derek H. Sleeman">D. Sleeman</a> and N. Bernsen, Lawrence Erlbaum Associates, pp 203–231, 1992.</li> <li><a href="/wiki/Leon_Sterling" title="Leon Sterling">Leon Sterling</a> and <a href="/wiki/Ehud_Shapiro" title="Ehud Shapiro">Ehud Shapiro</a>, The Art of Prolog: Advanced Programming Techniques, 1994, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-262-19338-8" title="Special:BookSources/0-262-19338-8">0-262-19338-8</a>.</li> <li>David H D Warren, Luis M. Pereira and Fernando Pereira, Prolog - the language and its implementation compared with Lisp. ACM SIGART Bulletin archive, Issue 64. Proceedings of the 1977 symposium on Artificial intelligence and programming languages, pp 109–115.</li></ul> </div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style 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<li><a href="/wiki/Non-English-based_programming_languages" title="Non-English-based programming languages">Non-English-based</a></li> <li><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /> <a href="/wiki/Category:Programming_languages" title="Category:Programming languages">Category</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style data-mw-deduplicate="TemplateStyles:r886047488">.mw-parser-output .nobold{font-weight:normal}</style></div><div role="navigation" class="navbox" aria-labelledby="ISO_standards_by_standard_number" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:ISO_standards" title="Template:ISO standards"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:ISO_standards" title="Template talk:ISO standards"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:ISO_standards" title="Special:EditPage/Template:ISO standards"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="ISO_standards_by_standard_number" style="font-size:114%;margin:0 4em"><a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">ISO</a> standards by standard number</div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div>List of <a href="/wiki/List_of_ISO_standards" title="List of ISO standards">ISO standards</a> – <a href="/wiki/List_of_ISO_romanizations" title="List of ISO romanizations">ISO romanizations</a> – <a href="/wiki/List_of_IEC_standards" title="List of IEC standards">IEC standards</a></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">1–9999</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ISO_1" title="ISO 1">1</a></li> <li><a href="/wiki/ISO_2" title="ISO 2">2</a></li> <li><a href="/wiki/Renard_series" title="Renard series">3</a></li> <li><a href="/wiki/ISO_4" title="ISO 4">4</a></li> <li><a href="/wiki/Film_speed" title="Film speed">6</a></li> <li><a href="/wiki/British_Standard_Pipe" title="British Standard Pipe">7</a></li> <li><a href="/wiki/ISO_9" title="ISO 9">9</a></li> <li><a href="/wiki/A440_(pitch_standard)" title="A440 (pitch standard)">16</a></li> <li><a href="/wiki/Renard_series" title="Renard series">17</a></li> <li><a href="/wiki/ISO_31" title="ISO 31">31</a> <ul><li><a href="/wiki/ISO_31-0" title="ISO 31-0">-0</a></li> <li><a href="/wiki/ISO_31-1" title="ISO 31-1">-1</a></li> <li><a href="/wiki/ISO_31-3" title="ISO 31-3">-3</a></li> <li><a href="/wiki/ISO_31-4" title="ISO 31-4">-4</a></li> <li><a href="/wiki/ISO_31-5" title="ISO 31-5">-5</a></li> <li><a href="/wiki/ISO_31-6" title="ISO 31-6">-6</a></li> <li><a href="/wiki/ISO_31-7" title="ISO 31-7">-7</a></li> <li><a href="/wiki/ISO_31-8" title="ISO 31-8">-8</a></li> <li><a href="/wiki/ISO_31-9" class="mw-redirect" title="ISO 31-9">-9</a></li> <li><a href="/wiki/ISO_31-10" title="ISO 31-10">-10</a></li> <li><a href="/wiki/ISO_31-11" title="ISO 31-11">-11</a></li> <li><a href="/wiki/ISO_31-12" class="mw-redirect" title="ISO 31-12">-12</a></li> <li><a href="/wiki/ISO_31-13" class="mw-redirect" title="ISO 31-13">-13</a></li></ul></li> <li><a href="/wiki/ISO_metric_screw_thread" title="ISO metric screw thread">68-1</a></li> <li><a href="/wiki/ISO_128" title="ISO 128">128</a></li> <li><a href="/wiki/ISO_216" title="ISO 216">216</a></li> <li><a href="/wiki/ISO_217" title="ISO 217">217</a></li> <li><a href="/wiki/Equal-loudness_contour" title="Equal-loudness contour">226</a></li> <li><a href="/wiki/British_Standard_Pipe" title="British Standard Pipe">228</a></li> <li><a href="/wiki/ISO_233" title="ISO 233">233</a></li> <li><a href="/wiki/ISO_259" title="ISO 259">259</a></li> <li><a href="/wiki/ISO_metric_screw_thread" title="ISO metric screw thread">261</a></li> <li><a href="/wiki/ISO_metric_screw_thread" title="ISO metric screw thread">262</a></li> <li><a href="/wiki/Kappa_number" title="Kappa number">302</a></li> <li><a href="/wiki/Vicat_softening_point" title="Vicat softening point">306</a></li> <li><a href="/wiki/Hazard_symbol#Ionizing_radiation_symbol" title="Hazard symbol">361</a></li> <li><a href="/wiki/Power_take-off" title="Power take-off">500</a></li> <li><a href="/wiki/Hot_shoe" title="Hot shoe">518</a></li> <li><a href="/wiki/Prontor-Compur" title="Prontor-Compur">519</a></li> <li><a href="/wiki/ISO_639" title="ISO 639">639</a> <ul><li><a href="/wiki/ISO_639-1" title="ISO 639-1">-1</a></li> <li><a href="/wiki/ISO_639-2" title="ISO 639-2">-2</a></li> <li><a href="/wiki/ISO_639-3" title="ISO 639-3">-3</a></li> <li><a href="/wiki/ISO_639-5" title="ISO 639-5">-5</a></li> <li><a href="/wiki/ISO_639-6" title="ISO 639-6">-6</a></li></ul></li> <li><a href="/wiki/ISO/IEC_646" title="ISO/IEC 646">646</a></li> <li><a href="/wiki/ISO_657" title="ISO 657">657</a></li> <li><a href="/wiki/ISO_668" title="ISO 668">668</a></li> <li><a href="/wiki/ISO_690" title="ISO 690">690</a></li> <li><a href="/wiki/ISO_704" title="ISO 704">704</a></li> <li><a href="/wiki/ISO_732" title="ISO 732">732</a></li> <li><a href="/wiki/Antimagnetic_watch" title="Antimagnetic watch">764</a></li> <li><a href="/wiki/Hole_punch" title="Hole punch">838</a></li> <li><a href="/wiki/ISO_843" title="ISO 843">843</a></li> <li><a href="/wiki/ISO_860" title="ISO 860">860</a></li> <li><a href="/wiki/ISO_898" title="ISO 898">898</a></li> <li><a href="/wiki/ISO_965" title="ISO 965">965</a></li> <li><a href="/wiki/ISO_999" title="ISO 999">999</a></li> <li><a href="/wiki/ISO_1000" title="ISO 1000">1000</a></li> <li><a href="/wiki/Magnetic_ink_character_recognition" title="Magnetic ink character recognition">1004</a></li> <li><a href="/wiki/135_film" title="135 film">1007</a></li> <li><a href="/wiki/OCR-A" title="OCR-A">1073-1</a></li> <li><a href="/wiki/OCR-B" title="OCR-B">1073-2</a></li> <li><a href="/wiki/Longitudinal_redundancy_check" title="Longitudinal redundancy check">1155</a></li> <li><a href="/wiki/Shock-resistant_watch#ISO_1413_shock-resistant_standard" title="Shock-resistant watch">1413</a></li> <li><a href="/wiki/ALGOL_60" title="ALGOL 60">1538</a></li> <li><a href="/wiki/ISO_1629" title="ISO 1629">1629</a></li> <li><a href="/wiki/ISO_1745" title="ISO 1745">1745</a></li> <li><a href="/wiki/COBOL" title="COBOL">1989</a></li> <li><a href="/wiki/ISO_2014" title="ISO 2014">2014</a></li> <li><a href="/wiki/ISO_2015" title="ISO 2015">2015</a></li> <li><a href="/wiki/ISO/IEC_2022" title="ISO/IEC 2022">2022</a></li> <li><a href="/wiki/ISO_2033" title="ISO 2033">2033</a></li> <li><a href="/wiki/ISO_2047" title="ISO 2047">2047</a></li> <li><a href="/wiki/ISBN" title="ISBN">2108</a></li> <li><a href="/wiki/ISO_2145" title="ISO 2145">2145</a></li> <li><a href="/wiki/ISO_2146" title="ISO 2146">2146</a></li> <li><a href="/wiki/Film_speed" title="Film speed">2240</a></li> <li><a href="/wiki/Water_Resistant_mark" title="Water Resistant mark">2281</a></li> <li><a href="/wiki/International_Standard_Atmosphere" title="International Standard Atmosphere">2533</a></li> <li><a href="/wiki/ISO_2709" title="ISO 2709">2709</a></li> <li><a href="/wiki/ISO_2711" title="ISO 2711">2711</a></li> <li><a href="/wiki/Film_speed" title="Film speed">2720</a></li> <li><a href="/wiki/ISO_2788" title="ISO 2788">2788</a></li> <li><a href="/wiki/ISO_2848" title="ISO 2848">2848</a></li> <li><a href="/wiki/ISO_2852" title="ISO 2852">2852</a></li> <li><a href="/wiki/ISO_2921" title="ISO 2921">2921</a></li> <li><a href="/wiki/126_film" title="126 film">3029</a></li> <li><a href="/wiki/ISO_3103" title="ISO 3103">3103</a></li> <li><a href="/wiki/ISO_3166" title="ISO 3166">3166</a> <ul><li><a href="/wiki/ISO_3166-1" title="ISO 3166-1">-1</a></li> <li><a href="/wiki/ISO_3166-2" title="ISO 3166-2">-2</a></li> <li><a href="/wiki/ISO_3166-3" title="ISO 3166-3">-3</a></li></ul></li> <li><a href="/wiki/International_Standard_Serial_Number" class="mw-redirect" title="International Standard Serial Number">3297</a></li> <li><a href="/wiki/ISO_3307" title="ISO 3307">3307</a></li> <li><a href="/wiki/O-ring" title="O-ring">3601</a></li> <li><a href="/wiki/Kunrei-shiki_romanization" title="Kunrei-shiki romanization">3602</a></li> <li><a href="/wiki/ISO_3864" title="ISO 3864">3864</a></li> <li><a href="/wiki/International_Standard_Recording_Code" title="International Standard Recording Code">3901</a></li> <li><a href="/wiki/FDI_World_Dental_Federation_notation" title="FDI World Dental Federation notation">3950</a></li> <li><a href="/wiki/ISO_3977" title="ISO 3977">3977</a></li> <li><a href="/wiki/ISO_4031" title="ISO 4031">4031</a></li> <li><a href="/wiki/ISO_4157" class="mw-redirect" title="ISO 4157">4157</a></li> <li><a href="/wiki/ISO_4165" title="ISO 4165">4165</a></li> <li><a href="/wiki/ISO_4217" title="ISO 4217">4217</a></li> <li><a href="/wiki/ISO/IEC_4909" title="ISO/IEC 4909">4909</a></li> <li><a href="/wiki/ISO/IEC_5218" title="ISO/IEC 5218">5218</a></li> <li><a href="/wiki/ISO_5426" title="ISO 5426">5426</a></li> <li><a href="/wiki/ISO_5427" title="ISO 5427">5427</a></li> <li><a href="/wiki/ISO_5428" title="ISO 5428">5428</a></li> <li><a href="/wiki/Accuracy_and_precision" title="Accuracy and precision">5725</a></li> <li><a href="/wiki/ISO_5775" title="ISO 5775">5775</a></li> <li><a href="/wiki/ISO_5776" title="ISO 5776">5776</a></li> <li><a href="/wiki/Film_speed" title="Film speed">5800</a></li> <li><a href="/wiki/Flowchart" title="Flowchart">5807</a></li> <li><a href="/wiki/ISO_5964" title="ISO 5964">5964</a></li> <li><a href="/wiki/International_Securities_Identification_Number" title="International Securities Identification Number">6166</a></li> <li><a href="/wiki/ISO_6344" title="ISO 6344">6344</a></li> <li><a href="/wiki/ISO_6346" title="ISO 6346">6346</a></li> <li><a href="/wiki/Minimal_BASIC" title="Minimal BASIC">6373</a></li> <li><a href="/wiki/ISO_6385" title="ISO 6385">6385</a></li> <li><a href="/wiki/Water_Resistant_mark" title="Water Resistant mark">6425</a></li> <li><a href="/wiki/ANSI_escape_code" title="ANSI escape code">6429</a></li> <li><a href="/wiki/ISO_6438" title="ISO 6438">6438</a></li> <li><a href="/wiki/ISO/IEC_6523" title="ISO/IEC 6523">6523</a></li> <li><a href="/wiki/ISO_6709" title="ISO 6709">6709</a></li> <li><a href="/wiki/ISO_6943" title="ISO 6943">6943</a></li> <li><a href="/wiki/ISO_7001" title="ISO 7001">7001</a></li> <li><a href="/wiki/ISO_7002" title="ISO 7002">7002</a></li> <li><a href="/wiki/ISO_7010" title="ISO 7010">7010</a></li> <li><a href="/wiki/ISO_7027" title="ISO 7027">7027</a></li> <li><a href="/wiki/ISO/IEC_7064" title="ISO/IEC 7064">7064</a></li> <li><a href="/wiki/Pinyin" title="Pinyin">7098</a></li> <li><a href="/wiki/Pascal_(programming_language)" title="Pascal (programming language)">7185</a></li> <li><a href="/wiki/ISO_7200" title="ISO 7200">7200</a></li> <li><a href="/wiki/OSI_model" title="OSI model">7498</a> <ul><li><a href="/wiki/OSI_model" title="OSI model">-1</a></li></ul></li> <li><a href="/wiki/ISO_7637" title="ISO 7637">7637</a></li> <li><a href="/wiki/ISO_7736" title="ISO 7736">7736</a></li> <li><a href="/wiki/ISO/IEC_7810" title="ISO/IEC 7810">7810</a></li> <li><a href="/wiki/ISO/IEC_7811" title="ISO/IEC 7811">7811</a></li> <li><a href="/wiki/ISO/IEC_7812" title="ISO/IEC 7812">7812</a></li> <li><a href="/wiki/ISO/IEC_7813" title="ISO/IEC 7813">7813</a></li> <li><a href="/wiki/ISO/IEC_7816" title="ISO/IEC 7816">7816</a></li> <li><a href="/wiki/Graphical_Kernel_System" title="Graphical Kernel System">7942</a></li> <li><a href="/wiki/ISO_8000" title="ISO 8000">8000</a></li> <li><a href="/wiki/On-board_diagnostics" title="On-board diagnostics">8093</a></li> <li><a href="/wiki/ISO_8178" title="ISO 8178">8178</a></li> <li><a href="/wiki/Fuel_oil" title="Fuel oil">8217</a></li> <li><a href="/wiki/ISO_8373" class="mw-redirect" title="ISO 8373">8373</a></li> <li><a href="/wiki/ISO_8501-1" title="ISO 8501-1">8501-1</a></li> <li><a href="/wiki/FTAM" title="FTAM">8571</a></li> <li><a href="/wiki/ISO_8583" title="ISO 8583">8583</a></li> <li><a href="/wiki/ISO_8601" title="ISO 8601">8601</a></li> <li><a href="/wiki/Open_Document_Architecture" title="Open Document Architecture">8613</a></li> <li><a href="/wiki/Computer_Graphics_Metafile" title="Computer Graphics Metafile">8632</a></li> <li><a href="/wiki/Graphical_Kernel_System" title="Graphical Kernel System">8651</a></li> <li><a href="/wiki/ISO/IEC_8652" title="ISO/IEC 8652">8652</a></li> <li><a href="/wiki/ISO_8691" title="ISO 8691">8691</a></li> <li><a href="/wiki/Graphical_Kernel_System" title="Graphical Kernel System">8805/8806</a></li> <li><a href="/wiki/Language_Of_Temporal_Ordering_Specification" class="mw-redirect" title="Language Of Temporal Ordering Specification">8807</a></li> <li><a href="/wiki/Fuse_(automotive)" class="mw-redirect" title="Fuse (automotive)">8820-5</a></li> <li><a href="/wiki/ISO/IEC_8859" title="ISO/IEC 8859">8859</a> <ul><li><a href="/wiki/ISO/IEC_8859-1" title="ISO/IEC 8859-1">-1</a></li> <li><a href="/wiki/ISO/IEC_8859-2" title="ISO/IEC 8859-2">-2</a></li> <li><a href="/wiki/ISO/IEC_8859-3" title="ISO/IEC 8859-3">-3</a></li> <li><a href="/wiki/ISO/IEC_8859-4" title="ISO/IEC 8859-4">-4</a></li> <li><a href="/wiki/ISO/IEC_8859-5" title="ISO/IEC 8859-5">-5</a></li> <li><a href="/wiki/ISO/IEC_8859-6" title="ISO/IEC 8859-6">-6</a></li> <li><a href="/wiki/ISO/IEC_8859-7" title="ISO/IEC 8859-7">-7</a></li> <li><a href="/wiki/ISO/IEC_8859-8" title="ISO/IEC 8859-8">-8</a></li> <li><a href="/wiki/ISO-8859-8-I" title="ISO-8859-8-I">-8-I</a></li> <li><a href="/wiki/ISO/IEC_8859-9" title="ISO/IEC 8859-9">-9</a></li> <li><a href="/wiki/ISO/IEC_8859-10" title="ISO/IEC 8859-10">-10</a></li> <li><a href="/wiki/ISO/IEC_8859-11" title="ISO/IEC 8859-11">-11</a></li> <li><a href="/wiki/ISO/IEC_8859-12" class="mw-redirect" title="ISO/IEC 8859-12">-12</a></li> <li><a href="/wiki/ISO/IEC_8859-13" title="ISO/IEC 8859-13">-13</a></li> <li><a href="/wiki/ISO/IEC_8859-14" title="ISO/IEC 8859-14">-14</a></li> <li><a href="/wiki/ISO/IEC_8859-15" title="ISO/IEC 8859-15">-15</a></li> <li><a href="/wiki/ISO/IEC_8859-16" title="ISO/IEC 8859-16">-16</a></li></ul></li> <li><a href="/wiki/Standard_Generalized_Markup_Language" title="Standard Generalized Markup Language">8879</a></li> <li><a href="/wiki/ISO_9000" class="mw-redirect" title="ISO 9000">9000/9001</a></li> <li><a href="/wiki/ASMO_449" title="ASMO 449">9036</a></li> <li><a href="/wiki/SQL" title="SQL">9075</a></li> <li><a href="/wiki/ISO/IEC_9126" title="ISO/IEC 9126">9126</a></li> <li><a href="/wiki/On-board_diagnostics" title="On-board diagnostics">9141</a></li> <li><a href="/wiki/Salt_spray_test" title="Salt spray test">9227</a></li> <li><a href="/wiki/ISO_9241" title="ISO 9241">9241</a></li> <li><a href="/wiki/File_Allocation_Table" title="File Allocation Table">9293</a></li> <li><a href="/wiki/Fiber_Distributed_Data_Interface" title="Fiber Distributed Data Interface">9314</a></li> <li><a href="/wiki/ISO_9362" title="ISO 9362">9362</a></li> <li><a href="/wiki/Shoe_size" title="Shoe size">9407</a></li> <li><a href="/wiki/CHILL" title="CHILL">9496</a></li> <li><a href="/wiki/Manufacturing_Message_Specification" title="Manufacturing Message Specification">9506</a></li> <li><a href="/wiki/ISO/IEC_9529" title="ISO/IEC 9529">9529</a></li> <li><a href="/wiki/ISO_9564" title="ISO 9564">9564</a></li> <li><a href="/wiki/PHIGS" title="PHIGS">9592/9593</a></li> <li><a href="/wiki/X.500" title="X.500">9594</a></li> <li><a href="/wiki/ISO_9660" title="ISO 9660">9660</a></li> <li><a href="/wiki/ISO/IEC_9797-1" title="ISO/IEC 9797-1">9797-1</a></li> <li><a href="/wiki/ISO_9897" title="ISO 9897">9897</a></li> <li><a href="/wiki/ANSI_C" title="ANSI C">9899</a></li> <li><a href="/wiki/POSIX" title="POSIX">9945</a></li> <li><a href="/wiki/Romanization_of_Georgian" title="Romanization of Georgian">9984</a></li> <li><a href="/wiki/Romanization_of_Armenian" title="Romanization of Armenian">9985</a></li> <li><a href="/wiki/ISO/IEC_9995" title="ISO/IEC 9995">9995</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">10000–19999</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ISO_10006" title="ISO 10006">10006</a></li> <li><a href="/wiki/ISO_10007" title="ISO 10007">10007</a></li> <li><a href="/wiki/ISO/IEC_10116" title="ISO/IEC 10116">10116</a></li> <li><a href="/wiki/Whirlpool_(hash_function)" title="Whirlpool (hash function)">10118-3</a></li> <li><a href="/wiki/ISO_10160" title="ISO 10160">10160</a></li> <li><a href="/wiki/ISO_10161" title="ISO 10161">10161</a></li> <li><a href="/wiki/Guidelines_for_the_Definition_of_Managed_Objects" title="Guidelines for the Definition of Managed Objects">10165</a></li> <li><a href="/wiki/Document_Style_Semantics_and_Specification_Language" title="Document Style Semantics and Specification Language">10179</a></li> <li><a href="/wiki/Pascal_(programming_language)#ISO/IEC_10206:1990_Extended_Pascal" title="Pascal (programming language)">10206</a></li> <li><a href="/wiki/ISO_10218" title="ISO 10218">10218</a></li> <li><a href="/wiki/Full_BASIC" title="Full BASIC">10279</a></li> <li><a href="/wiki/ISO_10303" title="ISO 10303">10303</a> <ul><li><a href="/wiki/EXPRESS_(data_modeling_language)" title="EXPRESS (data modeling language)">-11</a></li> <li><a href="/wiki/ISO_10303-21" title="ISO 10303-21">-21</a></li> <li><a href="/wiki/ISO_10303-22" title="ISO 10303-22">-22</a></li> <li><a href="/wiki/ISO_10303-28" title="ISO 10303-28">-28</a></li> <li><a href="/wiki/STEP-NC" title="STEP-NC">-238</a></li></ul></li> <li><a href="/wiki/Market_Identifier_Code" title="Market Identifier Code">10383</a></li> <li><a href="/wiki/ArmSCII" title="ArmSCII">10585</a></li> <li><a href="/wiki/IS-IS" title="IS-IS">10589</a></li> <li><a href="/wiki/ISO_10628" title="ISO 10628">10628</a></li> <li><a href="/wiki/Universal_Coded_Character_Set" title="Universal Coded Character Set">10646</a></li> <li><a href="/wiki/Torx" title="Torx">10664</a></li> <li><a href="/wiki/RM-ODP" title="RM-ODP">10746</a></li> <li><a href="/wiki/Multibus" title="Multibus">10861</a></li> <li><a href="/wiki/International_Standard_Music_Number" title="International Standard Music Number">10957</a></li> <li><a href="/wiki/ISO_10962" title="ISO 10962">10962</a></li> <li><a href="/wiki/ISO/IEC_10967" title="ISO/IEC 10967">10967</a></li> <li><a href="/wiki/ISO/IEEE_11073" title="ISO/IEEE 11073">11073</a></li> <li><a href="/wiki/ISO_11170" title="ISO 11170">11170</a></li> <li><a href="/wiki/MPEG-1" title="MPEG-1">11172</a></li> <li><a href="/wiki/ISO/IEC_11179" title="ISO/IEC 11179">11179</a></li> <li><a href="/wiki/ISO/IEC_11404" title="ISO/IEC 11404">11404</a></li> <li><a href="/wiki/JBIG" title="JBIG">11544</a></li> <li><a href="/wiki/ISO_11783" title="ISO 11783">11783</a></li> <li><a href="/wiki/ISO_11784_and_ISO_11785" title="ISO 11784 and ISO 11785">11784</a></li> <li><a href="/wiki/ISO_11784_and_ISO_11785" title="ISO 11784 and ISO 11785">11785</a></li> <li><a href="/wiki/ISO/IEC_11801" title="ISO/IEC 11801">11801</a></li> <li><a href="/wiki/Trusted_Platform_Module" title="Trusted Platform Module">11889</a></li> <li><a href="/wiki/CAN_bus#CAN_lower-layer_standards" title="CAN bus">11898</a></li> <li><a href="/wiki/ISO_11940" title="ISO 11940">11940</a> (<a href="/wiki/ISO_11940-2" title="ISO 11940-2">-2</a>)</li> <li><a href="/wiki/ISO/TR_11941" title="ISO/TR 11941">11941</a></li> <li><a href="/wiki/ISO/TR_11941" title="ISO/TR 11941">11941 (TR)</a></li> <li><a href="/wiki/ISO_11992" title="ISO 11992">11992</a></li> <li><a href="/wiki/ISO_12006" title="ISO 12006">12006</a></li> <li><a href="/wiki/DICOM" title="DICOM">12052</a></li> <li><a href="/wiki/ISO/IEC_TR_12182" title="ISO/IEC TR 12182">12182</a></li> <li><a href="/wiki/ISO/IEC_12207" title="ISO/IEC 12207">12207</a></li> <li><a href="/wiki/TIFF/EP" title="TIFF/EP">12234-2</a></li> <li><a href="/wiki/Linguistic_categories#ISO_12620_(ISO_TC37_Data_Category_Registry,_ISOcat)" title="Linguistic categories">12620</a></li> <li><a class="mw-selflink selflink">13211</a> <ul><li><a class="mw-selflink selflink">-1</a></li> <li><a class="mw-selflink selflink">-2</a></li></ul></li> <li><a href="/wiki/Isofix" title="Isofix">13216</a></li> <li><a href="/wiki/Topic_map" title="Topic map">13250</a></li> <li><a href="/wiki/ISO_13399" title="ISO 13399">13399</a></li> <li><a href="/wiki/ISO_13406-2" title="ISO 13406-2">13406-2</a></li> <li><a href="/wiki/110_film" title="110 film">13450</a></li> <li><a href="/wiki/ISO_13485" title="ISO 13485">13485</a></li> <li><a href="/wiki/ISO_13490" title="ISO 13490">13490</a></li> <li><a href="/wiki/ISO_13567" title="ISO 13567">13567</a></li> <li><a href="/wiki/Z_notation" title="Z notation">13568</a></li> <li><a href="/wiki/ISO_13584" title="ISO 13584">13584</a></li> <li><a href="/wiki/International_Bank_Account_Number" title="International Bank Account Number">13616</a></li> <li><a href="/wiki/ISLISP" title="ISLISP">13816</a></li> <li><a href="/wiki/MPEG-2" title="MPEG-2">13818</a></li> <li><a href="/wiki/ISO_14000" class="mw-redirect" title="ISO 14000">14000</a></li> <li><a href="/wiki/ISO_14031" title="ISO 14031">14031</a></li> <li><a href="/wiki/ISO_14224" title="ISO 14224">14224</a></li> <li><a href="/wiki/PDF/UA" title="PDF/UA">14289</a></li> <li><a href="/wiki/Horsepower" title="Horsepower">14396</a></li> <li><a href="/wiki/ISO/IEC_14443" title="ISO/IEC 14443">14443</a></li> <li><a href="/wiki/MPEG-4" title="MPEG-4">14496</a> <ul><li><a href="/wiki/MPEG-4_Part_2" title="MPEG-4 Part 2">-2</a></li> <li><a href="/wiki/MPEG-4_Part_3" title="MPEG-4 Part 3">-3</a></li> <li><a href="/wiki/Delivery_Multimedia_Integration_Framework" title="Delivery Multimedia Integration Framework">-6</a></li> <li><a href="/wiki/Advanced_Video_Coding" title="Advanced Video Coding">-10</a></li> <li><a href="/wiki/MPEG-4_Part_11" title="MPEG-4 Part 11">-11</a></li> <li><a href="/wiki/ISO_base_media_file_format" title="ISO base media file format">-12</a></li> <li><a href="/wiki/MP4_file_format" title="MP4 file format">-14</a></li> <li><a href="/wiki/MP4_file_format" title="MP4 file format">-17</a></li> <li><a href="/wiki/MP4_file_format" title="MP4 file format">-20</a></li></ul></li> <li><a href="/wiki/ISO_14617" title="ISO 14617">14617</a></li> <li><a href="/wiki/ISO_14644" title="ISO 14644">14644</a></li> <li><a href="/wiki/STEP-NC" title="STEP-NC">14649</a></li> <li><a href="/wiki/ISO/IEC_14651" title="ISO/IEC 14651">14651</a></li> <li><a href="/wiki/ISO_14698" title="ISO 14698">14698</a></li> <li><a href="/wiki/Software_maintenance" title="Software maintenance">14764</a></li> <li><a href="/wiki/C%2B%2B" title="C++">14882</a></li> <li><a href="/wiki/ISO_14971" title="ISO 14971">14971</a></li> <li><a href="/wiki/ISO_15022" title="ISO 15022">15022</a></li> <li><a href="/wiki/ISO_15189" title="ISO 15189">15189</a></li> <li><a href="/wiki/ISO/IEC_15288" title="ISO/IEC 15288">15288</a></li> <li><a href="/wiki/Ada_Semantic_Interface_Specification" title="Ada Semantic Interface Specification">15291</a></li> <li><a href="/wiki/ISO_15398" title="ISO 15398">15398</a></li> <li><a href="/wiki/Common_Criteria" title="Common Criteria">15408</a></li> <li><a href="/wiki/JPEG_2000" title="JPEG 2000">15444</a> <ul><li><a href="/wiki/Motion_JPEG_2000" title="Motion JPEG 2000">-3</a></li> <li><a href="/wiki/JPIP" title="JPIP">-9</a></li></ul></li> <li><a href="/wiki/HTML" title="HTML">15445</a></li> <li><a href="/wiki/PDF417" title="PDF417">15438</a></li> <li><a href="/wiki/ISO/IEC_15504" title="ISO/IEC 15504">15504</a></li> <li><a href="/wiki/International_Standard_Identifier_for_Libraries_and_Related_Organizations" title="International Standard Identifier for Libraries and Related Organizations">15511</a></li> <li><a href="/wiki/ISO_15686" title="ISO 15686">15686</a></li> <li><a href="/wiki/ISO/IEC_15693" title="ISO/IEC 15693">15693</a></li> <li><a href="/wiki/International_Standard_Audiovisual_Number" title="International Standard Audiovisual Number">15706</a> <ul><li><a href="/wiki/International_Standard_Audiovisual_Number" title="International Standard Audiovisual Number">-2</a></li></ul></li> <li><a href="/wiki/International_Standard_Musical_Work_Code" title="International Standard Musical Work Code">15707</a></li> <li><a href="/wiki/ISO/IEC_15897" title="ISO/IEC 15897">15897</a></li> <li><a href="/wiki/ISO_15919" title="ISO 15919">15919</a></li> <li><a href="/wiki/ISO_15924" title="ISO 15924">15924</a></li> <li><a href="/wiki/ISO_15926" title="ISO 15926">15926</a></li> <li><a href="/wiki/ISO_15926_WIP" title="ISO 15926 WIP">15926 WIP</a></li> <li><a href="/wiki/PDF/X" title="PDF/X">15930</a></li> <li><a href="/wiki/MPEG-7" title="MPEG-7">15938</a></li> <li><a href="/wiki/MaxiCode" title="MaxiCode">16023</a></li> <li><a href="/wiki/ECMAScript" title="ECMAScript">16262</a></li> <li><a href="/wiki/Quality_function_deployment" title="Quality function deployment">16355-1</a></li> <li><a href="/wiki/Mixed_raster_content" title="Mixed raster content">16485</a></li> <li><a href="/wiki/PDF/VT" title="PDF/VT">16612-2</a></li> <li><a href="/wiki/ISO_16750" title="ISO 16750">16750</a></li> <li><a href="/wiki/IATF_16949" title="IATF 16949">16949 (TS)</a></li> <li><a href="/wiki/ISO/IEC_17024" title="ISO/IEC 17024">17024</a></li> <li><a href="/wiki/ISO/IEC_17025" title="ISO/IEC 17025">17025</a></li> <li><a href="/wiki/ISO_17100" title="ISO 17100">17100</a></li> <li><a href="/wiki/Open_Virtualization_Format" title="Open Virtualization Format">17203</a></li> <li><a href="/wiki/SDMX" title="SDMX">17369</a></li> <li><a href="/wiki/Legal_Entity_Identifier" title="Legal Entity Identifier">17442</a></li> <li><a href="/wiki/COLLADA" title="COLLADA">17506</a></li> <li><a href="/wiki/ISO/IEC_27002" title="ISO/IEC 27002">17799</a></li> <li><a href="/wiki/QR_code" title="QR code">18004</a></li> <li><a href="/wiki/ISO/IEC_18014" title="ISO/IEC 18014">18014</a></li> <li><a href="/wiki/JPEG_XL" title="JPEG XL">18181</a></li> <li><a href="/wiki/ISO_18245" title="ISO 18245">18245</a></li> <li><a href="/wiki/Process_Specification_Language" title="Process Specification Language">18629</a></li> <li><a href="/wiki/Photographic_Activity_Test" title="Photographic Activity Test">18916</a></li> <li><a href="/wiki/PDF/A" title="PDF/A">19005</a></li> <li><a href="/wiki/ISO_19011" title="ISO 19011">19011</a></li> <li><a href="/wiki/ISO_19092-1" class="mw-redirect" title="ISO 19092-1">19092</a> <ul><li><a href="/wiki/ISO_19092-1" class="mw-redirect" title="ISO 19092-1">-1</a></li> <li><a href="/wiki/ISO_19092-2" class="mw-redirect" title="ISO 19092-2">-2</a></li></ul></li> <li><a href="/wiki/ISO_19114" title="ISO 19114">19114</a></li> <li><a href="/wiki/Geospatial_metadata#ISO_19115:_Geographic_information_–_Metadata" title="Geospatial metadata">19115</a></li> <li><a href="/wiki/Simple_Features" title="Simple Features">19125</a></li> <li><a href="/wiki/Geography_Markup_Language#ISO_19136" title="Geography Markup Language">19136</a></li> <li><a href="/wiki/Shoe_size" title="Shoe size">19407</a></li> <li><a href="/wiki/ISO_19439" title="ISO 19439">19439</a></li> <li><a href="/wiki/Common_Object_Request_Broker_Architecture" title="Common Object Request Broker Architecture">19500</a></li> <li><a href="/wiki/Unified_Modeling_Language" title="Unified Modeling Language">19501</a></li> <li><a href="/wiki/Meta-Object_Facility" title="Meta-Object Facility">19502</a></li> <li><a href="/wiki/XML_Metadata_Interchange" title="XML Metadata Interchange">19503</a></li> <li><a href="/wiki/Unified_Modeling_Language" title="Unified Modeling Language">19505</a></li> <li><a href="/wiki/Knowledge_Discovery_Metamodel" title="Knowledge Discovery Metamodel">19506</a></li> <li><a href="/wiki/Object_Constraint_Language" title="Object Constraint Language">19507</a></li> <li><a href="/wiki/Meta-Object_Facility" title="Meta-Object Facility">19508</a></li> <li><a href="/wiki/XML_Metadata_Interchange" title="XML Metadata Interchange">19509</a></li> <li><a href="/wiki/Business_Process_Model_and_Notation" title="Business Process Model and Notation">19510</a></li> <li><a href="/wiki/ISO_19600" title="ISO 19600">19600</a></li> <li><a href="/wiki/ISO/IEC_19752" title="ISO/IEC 19752">19752</a></li> <li><a href="/wiki/RELAX_NG" title="RELAX NG">19757</a></li> <li><a href="/wiki/ISO/IEC_19770" title="ISO/IEC 19770">19770</a></li> <li><a href="/wiki/X3D" title="X3D">19775-1</a></li> <li><a href="/wiki/ISO/IEC_19794-5" title="ISO/IEC 19794-5">19794-5</a></li> <li><a href="/wiki/Cloud_Infrastructure_Management_Interface" title="Cloud Infrastructure Management Interface">19831</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">20000–29999</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ISO/IEC_20000" title="ISO/IEC 20000">20000</a></li> <li><a href="/wiki/ISO_20022" title="ISO 20022">20022</a></li> <li><a href="/wiki/ISO_20121" title="ISO 20121">20121</a></li> <li><a href="/wiki/ISO_20400" title="ISO 20400">20400</a></li> <li><a href="/wiki/Open_Data_Protocol" title="Open Data Protocol">20802</a></li> <li><a href="/wiki/Han_Xin_code" title="Han Xin code">20830</a></li> <li><a href="/wiki/MPEG-21" title="MPEG-21">21000</a></li> <li><a href="/wiki/ISO_21001" title="ISO 21001">21001</a></li> <li><a href="/wiki/International_Standard_Text_Code" title="International Standard Text Code">21047</a></li> <li><a href="/wiki/JPEG_XS" title="JPEG XS">21122</a></li> <li><a href="/wiki/ISO_21500" title="ISO 21500">21500</a></li> <li><a href="/wiki/ISO/IEC_21827" title="ISO/IEC 21827">21827</a></li> <li><a href="/wiki/ISO_22000" title="ISO 22000">22000</a></li> <li><a href="/wiki/ECMAScript" title="ECMAScript">22275</a></li> <li><a href="/wiki/ISO_22300" title="ISO 22300">22300</a></li> <li><a href="/wiki/ISO_22301" title="ISO 22301">22301</a></li> <li><a href="/wiki/ISO_22395" title="ISO 22395">22395</a></li> <li><a href="/wiki/ECMAScript_for_XML" title="ECMAScript for XML">22537</a></li> <li><a href="/wiki/MPEG-A" title="MPEG-A">23000</a></li> <li><a href="/wiki/MPEG-D" title="MPEG-D">23003</a></li> <li><a href="/wiki/MPEG-H" title="MPEG-H">23008</a></li> <li><a href="/wiki/Dynamic_Adaptive_Streaming_over_HTTP" title="Dynamic Adaptive Streaming over HTTP">23009</a></li> <li><a href="/wiki/Versatile_Video_Coding" title="Versatile Video Coding">23090-3</a></li> <li><a href="/wiki/MPEG-G" title="MPEG-G">23092</a></li> <li><a href="/wiki/Essential_Video_Coding" title="Essential Video Coding">23094-1</a></li> <li><a href="/wiki/LCEVC" title="LCEVC">23094-2</a></li> <li><a href="/wiki/C_Sharp_(programming_language)" title="C Sharp (programming language)">23270</a></li> <li><a href="/wiki/Common_Language_Infrastructure" title="Common Language Infrastructure">23271</a></li> <li><a href="/wiki/Linux_Standard_Base" title="Linux Standard Base">23360</a></li> <li><a href="/wiki/Rectangular_Micro_QR_Code" title="Rectangular Micro QR Code">23941</a></li> <li><a href="/wiki/PDF/E" title="PDF/E">24517</a></li> <li><a href="/wiki/Lexical_Markup_Framework" title="Lexical Markup Framework">24613</a></li> <li><a href="/wiki/ISO-TimeML" title="ISO-TimeML">24617</a></li> <li><a href="/wiki/Common_Logic" title="Common Logic">24707</a></li> <li><a href="/wiki/MicroPDF417" title="MicroPDF417">24728</a></li> <li><a href="/wiki/ISO_25178" title="ISO 25178">25178</a></li> <li><a href="/wiki/ISO_25964" title="ISO 25964">25964</a></li> <li><a href="/wiki/ISO_26000" title="ISO 26000">26000</a></li> <li><a href="/wiki/ISO_26262" title="ISO 26262">26262</a></li> <li><a href="/wiki/OpenDocument" title="OpenDocument">26300</a></li> <li><a href="/wiki/Digital_object_identifier" title="Digital object identifier">26324</a></li> <li><a href="/wiki/ISO/IEC_27000-series" class="mw-redirect" title="ISO/IEC 27000-series">27000 series</a></li> <li><a href="/wiki/ISO/IEC_27000" title="ISO/IEC 27000">27000</a></li> <li><a href="/wiki/ISO/IEC_27001" title="ISO/IEC 27001">27001</a></li> <li><a href="/wiki/ISO/IEC_27002" title="ISO/IEC 27002">27002</a></li> <li><a href="/wiki/ISO/IEC_27005" title="ISO/IEC 27005">27005</a></li> <li><a href="/wiki/ISO/IEC_27006" title="ISO/IEC 27006">27006</a></li> <li><a href="/wiki/International_Standard_Name_Identifier" title="International Standard Name Identifier">27729</a></li> <li><a href="/wiki/ISO_28000" title="ISO 28000">28000</a></li> <li>29110</li> <li><a href="/wiki/Requirements_engineering" title="Requirements engineering">29148</a></li> <li><a href="/wiki/JPEG_XR" title="JPEG XR">29199-2</a></li> <li><a href="/wiki/Office_Open_XML" title="Office Open XML">29500</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">30000+</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Ruby_(programming_language)" title="Ruby (programming language)">30170</a></li> <li><a href="/wiki/ISO_31000" title="ISO 31000">31000</a></li> <li><a href="/wiki/PDF" title="PDF">32000</a></li> <li><a href="/wiki/ISO_37001" title="ISO 37001">37001</a></li> <li><a href="/wiki/ISO/IEC_38500" title="ISO/IEC 38500">38500</a></li> <li><a href="/wiki/Graph_Query_Language" title="Graph Query Language">39075</a></li> <li><a href="/wiki/Web_Content_Accessibility_Guidelines" title="Web Content Accessibility Guidelines">40500</a></li> <li><a href="/wiki/ISO/IEC_42010" title="ISO/IEC 42010">42010</a></li> <li><a href="/wiki/ISO_45001" title="ISO 45001">45001</a></li> <li><a href="/wiki/ISO_50001" title="ISO 50001">50001</a></li> <li><a href="/wiki/ISO_55000" title="ISO 55000">55000</a></li> <li><a href="/wiki/ISO_56000" title="ISO 56000">56000</a></li> <li><a href="/wiki/ISO/IEC_80000" title="ISO/IEC 80000">80000</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, 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