<!DOCTYPE html>
<html class="client-nojs vector-feature-night-mode-disabled vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-sticky-header-enabled" lang="en" dir="ltr"><head>
<meta charset="UTF-8">
<title>OBJ (programming language)</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="canonical" href="https://en.wikipedia.org/wiki/OBJ_(programming_language)"> <link href="./mw/ext.cite.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.icons.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.search.codex.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/user.styles.css" rel="stylesheet" type="text/css">
<meta name="ResourceLoaderDynamicStyles" content="">
<link rel="stylesheet" type="text/css" href="./mw/site.styles.css">
<link rel="stylesheet" type="text/css" href="./mw/noscript.css">
<link rel="stylesheet" type="text/css" href="./footer.css">
<link rel="stylesheet" type="text/css" href="./vector-2022.css">
</head>
<body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-OBJ_programming_language rootpage-OBJ_programming_language skin-vector-2022 action-view">
<div class="mw-page-container">
<div class="mw-page-container-inner">
<div class="mw-content-container">
<main id="content" class="mw-body">
<header class="mw-body-header vector-page-titlebar">
<h1 id="firstHeading" class="firstHeading mw-first-heading">
<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">OBJ (programming language)</span></span>
</h1>
</header>
<a id="top"></a>
<div id="bodyContent" class="vector-body ve-init-mw-desktopArticleTarget-targetContainer" aria-labelledby="firstHeading" data-mw-ve-target-container="">
<div id="mw-content-text" class="mw-body-content mw-content-ltr" lang="en" dir="ltr"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><p><b>OBJ</b> is a <a href="Programming_language" title="Programming language">programming language</a> family introduced by <a href="Joseph_Goguen" title="Joseph Goguen">Joseph Goguen</a> in 1976, and further worked on by <a href="Jose_Meseguer" title="Jose Meseguer">Jose Meseguer</a>.
</p>
<meta property="mw:PageProp/toc">
<div class="mw-heading mw-heading2"><h2 id="Overview">Overview</h2></div>
<p>It is a family of <a href="Declarative_programming" title="Declarative programming">declarative</a> "ultra high-level" languages. It features <a href="Abstract_data_type" title="Abstract data type">abstract types</a>, generic modules, subsorts (subtypes with <a href="Multiple_inheritance" title="Multiple inheritance">multiple inheritance</a>), <a href="Pattern_matching" title="Pattern matching">pattern-matching</a> modulo equations, E-strategies (user control over <a href="Lazy_evaluation" title="Lazy evaluation">laziness</a>), module expressions (for combining modules), theories and views (for describing module interfaces) for the massively parallel RRM (rewrite rule machine).<sup id="cite_ref-foldoc_1-0" class="reference"><a href="#cite_note-foldoc-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
</p><p>Members of the OBJ family of languages include CafeOBJ, Eqlog, FOOPS, Kumo, <a href="Maude_system" title="Maude system">Maude</a>, <a href="OBJ2" class="mw-redirect" title="OBJ2">OBJ2</a>, and <a href="OBJ3" class="mw-redirect" title="OBJ3">OBJ3</a>.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="OBJ2">OBJ2</h2></div>
<p><b>OBJ2</b> is a <a href="Programming_language" title="Programming language">programming language</a> with Clear-like parametrised modules and a functional system based on equations.
</p>
<div class="mw-heading mw-heading2"><h2 id="OBJ3">OBJ3</h2></div>
<p><b>OBJ3</b> is a version of OBJ based on <a href="Order_theory" title="Order theory">order</a>-sorted <a href="Rewriting" title="Rewriting">rewriting</a>. OBJ3 is <a href="Intelligent_agent" title="Intelligent agent">agent</a>-oriented and runs on <a href="Kyoto_Common_Lisp" title="Kyoto Common Lisp">Kyoto Common Lisp</a> AKCL.
</p>
<div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div>
<ul><li><a href="Automated_theorem_proving" title="Automated theorem proving">Automated theorem proving</a></li>
<li><a href="Comparison_of_programming_languages" title="Comparison of programming languages">Comparison of programming languages</a></li>
<li><a href="Formal_methods" title="Formal methods">Formal methods</a></li></ul>
<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
<style data-mw-deduplicate="TemplateStyles:r1239543626">
/* start https://en.wikipedia.org/ */
.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}
/* end https://en.wikipedia.org/ */
</style><div class="reflist">
<div class="mw-references-wrap"><ol class="references">
<li id="cite_note-foldoc-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-foldoc_1-0">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1041539562">
/* start https://en.wikipedia.org/ */
.mw-parser-output .citation{word-wrap:break-word}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}
/* end https://en.wikipedia.org/ */
</style><span class="citation foldoc">This article is based on material taken from <a rel="nofollow" class="external text" href="https://foldoc.org/OBJ">OBJ</a> at the <i><a href="Free_On-line_Dictionary_of_Computing" title="Free On-line Dictionary of Computing">Free On-line Dictionary of Computing</a></i> prior to 1 November 2008 and incorporated under the "relicensing" terms of the <a href="GNU_Free_Documentation_License" title="GNU Free Documentation License">GFDL</a>, version 1.3 or later.</span></span>
</li>
<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://cseweb.ucsd.edu/~goguen/sys/obj.html">The OBJ family</a></span>
</li>
</ol></div></div>
<ul><li>J. A. Goguen, <a rel="nofollow" class="external text" href="http://cseweb.ucsd.edu/~goguen/pps/utyop.ps">Higher-Order Functions Considered Unnecessary for Higher-Order Programming</a>. In <i>Research Topics in Functional Programming</i> (June 1990). pp. 309–351.</li>
<li>"Principles of OBJ2", K. Futatsugi et al., 12th POPL, ACM 1985, pp. 52–66.</li>
<li><style data-mw-deduplicate="TemplateStyles:r1238218222">
/* start https://en.wikipedia.org/ */
.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("./mw/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("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/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}}
/* end https://en.wikipedia.org/ */
</style><cite id="CITEREFJ._A._GoguenT._WinklerJ._MeseguerK._Futatsugi2000" class="citation cs2">J. A. Goguen; T. Winkler; J. Meseguer; K. Futatsugi; J.-P. Jouannaud (2000), "Introducing OBJ", in J. A. Goguen; G. Malcolm (eds.), <i>Software Engineering with OBJ: Algebraic Specification in Action</i>, Springer Science+Business Media, New York, NY, pp. <span class="nowrap">3–</span>167, <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4757-6541-0</bdi></cite></li></ul>
<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>
<ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20051028140059/http://vl.fmnet.info/obj/">The OBJ archive</a></li>
<li><a rel="nofollow" class="external text" href="https://cseweb.ucsd.edu/~goguen/sys/obj.html">The OBJ family</a></li>
<li><a rel="nofollow" class="external text" href="https://www-cse.ucsd.edu/~goguen/pps/iobj.ps">Information and OBJ3 manual</a>, <a href="PostScript" title="PostScript">PostScript</a> format</li></ul>
<style data-mw-deduplicate="TemplateStyles:r1271159938">
/* start https://en.wikipedia.org/ */
.mw-parser-output .asbox{position:relative;overflow:hidden}.mw-parser-output .asbox table{background:transparent}.mw-parser-output .asbox p{margin:0}.mw-parser-output .asbox p+p{margin-top:0.25em}.mw-parser-output .asbox-body{font-style:italic}.mw-parser-output .asbox-note{font-size:smaller}.mw-parser-output .asbox .navbar{position:absolute;top:-0.75em;right:1em;display:none}.mw-parser-output :not(p):not(.asbox)+style+.asbox,.mw-parser-output :not(p):not(.asbox)+link+.asbox{margin-top:3em}
/* end https://en.wikipedia.org/ */
</style></div><!--htdig_noindex--><div><div class="zim-footer">
This article is issued from <a class="external text" title="Last edited on 2025-08-06" href="https://en.wikipedia.org/wiki/?title=OBJ_(programming_language)&oldid=1304534714">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.
</div>
</div><!--/htdig_noindex--></div>
</div>
</main>
</div>
</div>
</div>
</body></html>