41 lines
86 KiB
HTML
41 lines
86 KiB
HTML
|
<!doctype html>
|
|||
|
|
<html lang="en" dir="ltr" class="docs-wrapper plugin-docs plugin-id-default docs-version-current docs-doc-page docs-doc-id-meta-object-protocol/dictionary/compute-applicable-methods-using-classes" data-has-hydrated="false">
|
|||
|
|
<head>
|
|||
|
|
<meta charset="UTF-8">
|
|||
|
|
<meta name="generator" content="Docusaurus v3.0.1">
|
|||
|
|
<title data-rh="true">compute-applicable-methods-using-classes | Common Lisp (New) Language Reference</title><meta data-rh="true" name="viewport" content="width=device-width,initial-scale=1"><meta data-rh="true" name="twitter:card" content="summary_large_image"><meta data-rh="true" property="og:image" content="https://lisp-docs.github.io/cl-language-reference/img/1024px-Lisp_logo.svg.png"><meta data-rh="true" name="twitter:image" content="https://lisp-docs.github.io/cl-language-reference/img/1024px-Lisp_logo.svg.png"><meta data-rh="true" property="og:url" content="https://lisp-docs.github.io/cl-language-reference/meta-object-protocol/dictionary/compute-applicable-methods-using-classes"><meta data-rh="true" property="og:locale" content="en"><meta data-rh="true" name="docusaurus_locale" content="en"><meta data-rh="true" name="docsearch:language" content="en"><meta data-rh="true" name="google-site-verification" content="Vzaw013_bfdKeUVG89Ch3W1zC9_vH9ID2dPB9Dz0vr0"><meta data-rh="true" name="docusaurus_version" content="current"><meta data-rh="true" name="docusaurus_tag" content="docs-default-current"><meta data-rh="true" name="docsearch:version" content="current"><meta data-rh="true" name="docsearch:docusaurus_tag" content="docs-default-current"><meta data-rh="true" property="og:title" content="compute-applicable-methods-using-classes | Common Lisp (New) Language Reference"><meta data-rh="true" name="description" content="Generic Function COMPUTE-APPLICABLE-METHODS-USING-CLASSES"><meta data-rh="true" property="og:description" content="Generic Function COMPUTE-APPLICABLE-METHODS-USING-CLASSES"><link data-rh="true" rel="icon" href="../../img/favicon.ico"><link data-rh="true" rel="canonical" href="compute-applicable-methods-using-classes.html"><link data-rh="true" rel="alternate" href="compute-applicable-methods-using-classes.html" hreflang="en"><link data-rh="true" rel="alternate" href="compute-applicable-methods-using-classes.html" hreflang="x-default"><link data-rh="true" rel="preconnect" href="https://C1F2Q5VM6X-dsn.algolia.net" crossorigin="anonymous"><link rel="preconnect" href="https://www.google-analytics.com">
|
|||
|
|
<link rel="preconnect" href="https://www.googletagmanager.com">
|
|||
|
|
<script async src="https://www.googletagmanager.com/gtag/js?id=G-8TJCE4NSF8"></script>
|
|||
|
|
<script>function gtag(){dataLayer.push(arguments)}window.dataLayer=window.dataLayer||[],gtag("js",new Date),gtag("config","G-8TJCE4NSF8",{})</script>
|
|||
|
|
|
|||
|
|
|
|||
|
|
<link rel="search" type="application/opensearchdescription+xml" title="Common Lisp (New) Language Reference" href="../../opensearch.xml"><link rel="stylesheet" href="../../assets/css/styles.f13b59fe.css">
|
|||
|
|
<script src="../../assets/js/runtime~main.02699c25.js" defer="defer"></script>
|
|||
|
|
<script src="../../assets/js/main.4f0a7a76.js" defer="defer"></script>
|
|||
|
|
</head>
|
|||
|
|
<body class="navigation-with-keyboard">
|
|||
|
|
<script>!function(){function t(t){document.documentElement.setAttribute("data-theme",t)}var e=function(){try{return new URLSearchParams(window.location.search).get("docusaurus-theme")}catch(t){}}()||function(){try{return localStorage.getItem("theme")}catch(t){}}();t(null!==e?e:"light")}(),function(){try{const c=new URLSearchParams(window.location.search).entries();for(var[t,e]of c)if(t.startsWith("docusaurus-data-")){var a=t.replace("docusaurus-data-","data-");document.documentElement.setAttribute(a,e)}}catch(t){}}()</script><div id="__docusaurus"><div role="region" aria-label="Skip to main content"><a class="skipToContent_fXgn" href="compute-applicable-methods-using-classes.html#__docusaurus_skipToContent_fallback">Skip to main content</a></div><nav aria-label="Main" class="navbar navbar--fixed-top"><div class="navbar__inner"><div class="navbar__items"><button aria-label="Toggle navigation bar" aria-expanded="false" class="navbar__toggle clean-btn" type="button"><svg width="30" height="30" viewBox="0 0 30 30" aria-hidden="true"><path stroke="currentColor" stroke-linecap="round" stroke-miterlimit="10" stroke-width="2" d="M4 7h22M4 15h22M4 23h22"></path></svg></button><a href="../../../index.html" target="_blank" rel="noopener noreferrer" class="navbar__brand"><div class="navbar__logo"><img src="../../img/logo.svg" alt="Lisp Logo" class="themedComponent_mlkZ themedComponent--light_NVdE"><img src="../../img/logo.svg" alt="Lisp Logo" class="themedComponent_mlkZ themedComponent--dark_xIcU"></div><b class="navbar__title text--truncate">Common Lisp Docs</b></a><a href="../../../docs/tutorial/index.html" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">Tutorial</a><a href="../../index.html" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">Technical Reference</a><a href="../../../docs/whylisp.html" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">Why Lisp?</a><a href="../../../docs/howto.html" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">Guides</a></div><div class="navbar__items navbar__items--right"><a href="../../../docs/contribute.html" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">Contribute!</a><a href="../../../docs/help.html" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">Getting Help</a><a href="../../../docs/about.html" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">About</a><a href="../../../blog.html" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">Blog</a><a href="https://github.com/lisp-docs" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">GitHub<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_nPIU"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a><div class="toggle_vylO colorModeToggle_DEke"><button class="clean-btn toggleButton_gllP toggleButtonDisabled_aARS" type="button" disabled="" title="Switch between dark and light mode (currently light mode)" aria-label="Switch between dark and light mode (currently light mode)" aria-live="polite"><svg viewBox="0 0 24 24" width="24" height="24" class="lightToggleIcon_pyhR"><path fill="currentColor" d="M12,9c1.65,0,3,1.35,3,3s-1.35,3-3,3s-3-1.35-3-3S10.35,9,12,9 M12,7c-2.76,0-5,2.24-5,5s2.24,5,5,5s5-2.24,5-5 S14.76,7,12,7L12,7z M2,13l2,0c0.55,0,1-0.45,1-1s-0.45-1-1-1l-2,0c-0.55,0-1,0.45-1,1S1.45,13,2,13z M20,13l2,0c0.55,0,1-0.45,1-1 s-0.45-1-1-1l-2,0c-0.55,0-1,0.45-1,1S19.45,13,20,13z M11,2v2c0,0.55,0.45,1,1,1s1-0.45,1-1V2c0-0.55-0.45-1-1-1S11,1.45,11,2z M11,20v2c0,0.55,0.45,1,1,1s1-0.45,1-1v-2c0-0.55-0.45-1-1-1C11.45,19,11,19.45,11,20z M5.99,4.58c-0.39-0.39-1.03-0.39-1.41,0 c-0.39,0.39-0.39,1.03,0,1.41l1.06,1.06c0.39,0.39,1.03,0.39,1.41,0s0.39-1.03,0-1.41L5.99,4.58z M18.36,16.95 c-0.39-0.39-1.03-0.39-1.41,0c-0.39,0.39-0.39,1.03,0,1.41l1.06,1.06c0.39,0.39,1.03,0.39,1.41,
|
|||
|
|
<p><em>Generic Function</em> <strong>COMPUTE-APPLICABLE-METHODS-USING-CLASSES</strong></p>
|
|||
|
|
<p><strong>Syntax:</strong></p>
|
|||
|
|
<p><strong>compute-applicable-methods-using-classes</strong> <em>generic-function</em> <em>classes</em> => <em>methods</em>, <em>ok</em></p>
|
|||
|
|
<p><strong>Arguments and values:</strong></p>
|
|||
|
|
<p><em>generic-function</em> -- A generic function metaobject.</p>
|
|||
|
|
<p><em>classes</em> -- A list of class metaobjects.</p>
|
|||
|
|
<p><em>methods</em> -- A (possibly empty) list of method metaobjects.</p>
|
|||
|
|
<p><em>ok</em> -- A generalized boolean.</p>
|
|||
|
|
<p><strong>Description:</strong></p>
|
|||
|
|
<p>This generic function is called to attempt to determine the method applicability of a generic function given only the classes of the required arguments.</p>
|
|||
|
|
<p>If it is possible to completely determine the ordered list of applicable methods based only on the supplied classes, this generic function returns that list as its first value and true as its second value. The returned list of method metaobjects is sorted by precedence order, the most specific method coming first. If no methods are applicable to arguments with the specified classes, the empty list and true are returned.</p>
|
|||
|
|
<p>If it is not possible to completely determine the ordered list of applicable methods based only on the supplied classes, this generic function returns an unspecified first value and false as its second value.</p>
|
|||
|
|
<p>When a generic function is invoked, the discriminating function must determine the ordered list of methods applicable to the arguments. Depending on the generic function and the arguments, this is done in one of three ways: using a memoized value; calling <strong>compute-applicable-methods-using-classes</strong> or calling<a href="https://lisp-docs.github.io/cl-language-reference/meta-object-protocol/compute-applicable-methods">compute-applicable-methods</a>. (Refer to the description of <a href="https://lisp-docs.github.io/cl-language-reference/meta-object-protocol/compute-discriminating-function">compute-discriminating-function</a> for the details of this process.)</p>
|
|||
|
|
<p>The following consistency relationship between <strong>compute-applicable-methods-using-classes</strong> and <a href="https://lisp-docs.github.io/cl-language-reference/meta-object-protocol/compute-applicable-methods">compute-applicable-methods</a> must be maintained: for any given generic function and set of arguments, if <strong>compute-applicable-methods-using-classes</strong> returns a second value of true, the first value must be equal to the value that would be returned by a corresponding call to <a href="https://lisp-docs.github.io/cl-language-reference/meta-object-protocol/compute-applicable-methods">compute-applicable-methods</a>. The results are undefined if a portable method on either of these generic functions causes this consistency to be violated.</p>
|
|||
|
|
<p>The list returned by this generic function will not be mutated by the implementation. The results are undefined if a portable program mutates the list returned by this generic function.</p>
|
|||
|
|
<p><strong>Methods:</strong></p>
|
|||
|
|
<hr>
|
|||
|
|
<h2 class="anchor anchorWithStickyNavbar_LWe7" id="compute-applicable-methods-using-classes-generic-function-standard-generic-function-arguments"><a href="https://lisp-docs.github.io/cl-language-reference/meta-object-protocol/compute-applicable-methods-using-classes-standard-generic-function"><strong>compute-applicable-methods-using-classes</strong> (<em>generic-function</em> standard-generic-function) <em>arguments</em></a><a href="compute-applicable-methods-using-classes.html#compute-applicable-methods-using-classes-generic-function-standard-generic-function-arguments" class="hash-link" aria-label="Direct link to compute-applicable-methods-using-classes-generic-function-standard-generic-function-arguments" title="Direct link to compute-applicable-methods-using-classes-generic-function-standard-generic-function-arguments"></a></h2>
|
|||
|
|
<p><strong>Remarks:</strong></p>
|
|||
|
|
<p>This generic function exists to allow user extensions which alter method lookup rules, but which base the new rules only on the classes of the required arguments, to take advantage of the class-based method lookup memoization found in many implementations. (There is of course no requirement for an implementation to provide this optimization.)</p>
|
|||
|
|
<p>Such an extension can be implemented by two methods, one on this generic function and one on <a href="https://lisp-docs.github.io/cl-language-reference/meta-object-protocol/compute-applicable-methods">compute-applicable-methods</a>. Whenever the user extension is in effect, the first method will return a second value of true. This should allow the implementation to absorb these cases into its own memoization scheme.</p>
|
|||
|
|
<p>To get appropriate performance, other kinds of extensions may require methods on <a href="https://lisp-docs.github.io/cl-language-reference/meta-object-protocol/compute-discriminating-function">compute-discriminating-function</a> which implement their own memoization scheme.</p></div><footer class="theme-doc-footer docusaurus-mt-lg"><div class="theme-doc-footer-edit-meta-row row"><div class="col"><a href="https://github.com/lisp-docs/cl-language-reference/tree/main/docs/meta-object-protocol/dictionary/compute-applicable-methods-using-classes.md" target="_blank" rel="noopener noreferrer" class="theme-edit-this-page"><svg fill="currentColor" height="20" width="20" viewBox="0 0 40 40" class="iconEdit_Z9Sw" aria-hidden="true"><g><path d="m34.5 11.7l-3 3.1-6.3-6.3 3.1-3q0.5-0.5 1.2-0.5t1.1 0.5l3.9 3.9q0.5 0.4 0.5 1.1t-0.5 1.2z m-29.5 17.1l18.4-18.5 6.3 6.3-18.4 18.4h-6.3v-6.2z"></path></g></svg>Edit this page</a></div><div class="col lastUpdated_vwxv"><span class="theme-last-updated">Last updated<!-- --> by <b>daninus14</b></span></div></div></footer></article><nav class="pagination-nav docusaurus-mt-lg" aria-label="Docs pages"><a class="pagination-nav__link pagination-nav__link--prev" href="compute-applicable-methods-using-classes-standard-generic-function.html"><div class="pagination-nav__sublabel">Previous</div><div class="pagination-nav__label">compute-applicable-methods-using-classes-standard-generic-function</div></a><a class="pagination-nav__link pagination-nav__link--next" href="compute-applicable-methods.html"><div class="pagination-nav__sublabel">Next</div><div class="pagination-nav__label">compute-applicable-methods</div></a></nav></div></div><div class="col col--3"><div class="tableOfContents_bqdL thin-scrollbar theme-doc-toc-desktop"><ul class="table-of-contents table-of-contents__left-border"><li><a href="compute-applicable-methods-using-classes.html#compute-applicable-methods-using-classes-generic-function-standard-generic-function-arguments" class="table-of-contents__link toc-highlight"><strong>compute-applicable-methods-using-classes</strong> (<em>generic-function</em> standard-generic-function) <em>arguments</em></a></li></ul></div></div></div></div></main></div></div></div><footer class="footer footer--dark"><div class="container container-fluid"><div class="row footer__links"><div class="col footer__col"><div class="footer__title">Docs</div><ul class="footer__items clean-list"><li class="footer__item"><a href="../../../docs/tutorial.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">Common Lisp Tutorial</a></li><li class="footer__item"><a href="../../index.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">Common Lisp Technical Reference</a></li><li class="footer__item"><a href="../../../docs/help.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">Help</a></li></ul></div><div class="col footer__col"><div class="footer__title">Community</div><ul class="footer__items clean-list"><li class="footer__item"><a href="https://stackoverflow.com/questions/tagged/common-lisp" target="_blank" rel="noopener noreferrer" class="footer__link-item">Stack Overflow<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_nPIU"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li><li class="footer__item"><a href="https://discord.gg/hhk46CE" target="_blank" rel="noopener noreferrer" class="footer__link-item">Discord<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_nPIU"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li><li class="footer__item"><a href="https://www.reddit.com/r/common_lisp" target="_blank" rel="noopener noreferrer" class="footer__link-item">Reddit<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_
|
|||
|
|
</body>
|
|||
|
|
</html>
|