52 lines
No EOL
42 KiB
HTML
52 lines
No EOL
42 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-chap-10/ba-c-dictionary/symbol_system-class" data-has-hydrated="false">
|
||
<head>
|
||
<meta charset="UTF-8">
|
||
<meta name="generator" content="Docusaurus v3.0.1">
|
||
<title data-rh="true">symbol | 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/chap-10/ba-c-dictionary/symbol_system-class"><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="symbol | Common Lisp (New) Language Reference"><meta data-rh="true" name="description" content="Expanded Reference: symbol"><meta data-rh="true" property="og:description" content="Expanded Reference: symbol"><link data-rh="true" rel="icon" href="../../img/favicon.ico"><link data-rh="true" rel="canonical" href="symbol_system-class.html"><link data-rh="true" rel="alternate" href="symbol_system-class.html" hreflang="en"><link data-rh="true" rel="alternate" href="symbol_system-class.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="symbol_system-class.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-0.39,0.39-0.39,1.03,0,1.41l1.06,1.06c0.39,0.39,1.03,0.39,1.41,0c0.39-0.39,0.39-1.03,0-1.41 L18.36,16.95z M19.42,5.99c0.39-0.39,0.39-1.03,0-1.41c-0.39-0.39-1.03-0.39-1.41,0l-1.06,1.06c-0.39,0.39-0.39,1.03,0,1.41 s1.03,0.39,1.41,0L19.42,5.99z M7.05,18.36c0.39-0.39,0.39-1.03,0-1.41c-0.39-0.39-1.03-0.39-1.41,0l-1.06,1.06 c-0.39,0.39-0.39,1.03,0,1.41s1.03,0.39,1.41,0L7.05,18.36z"></path></svg><svg viewBox="0 0 24 24" width="24" height="24" class="darkToggleIcon_wfgR"><path fill="currentColor" d="M9.37,5.51C9.19,6.15,9.1,6.82,9.1,7.5c0,4.08,3.32,7.4,7.4,7.4c0.68,0,1.35-0.09,1.99-0.27C17.45,17.19,14.93,19,12,19 c-3.86,0-7-3.14-7-7C5,9.07,6.81,6.55,9.37,5.51z M12,3c-4.97,0-9,4.03-9,9s4.03,9,9,9s9-4.03,9-9c0-0.46-0.04-0.92-0.1-1.36 c-0.98,1.37-2.58,2.26-4.4,2.26c-2.98,0-5.4-2.42-5.4-5.4c0-1.81,0.89-3.42,2.26-4.4C12.92,3.04,12.46,3,12,3L12,3z"></path></svg></button></div><div class="navbarSearchContainer_Bca1"><button type="button" class="DocSearch DocSearch-Button" aria-label="Search"><span class="DocSearch-Button-Container"><svg width="20" height="20" class="DocSearch-Search-Icon" viewBox="0 0 20 20"><path d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" stroke="currentColor" fill="none" fill-rule="evenodd" stroke-linecap="round" stroke-linejoin="round"></path></svg><span class="DocSearch-Button-Placeholder">Search</span></span><span class="DocSearch-Button-Keys"></span></button></div></div></div><div role="presentation" class="navbar-sidebar__backdrop"></div></nav><div id="__docusaurus_skipToContent_fallback" class="main-wrapper mainWrapper_z2l0"><div class="docsWrapper_hBAB"><button aria-label="Scroll back to top" class="clean-btn theme-back-to-top-button backToTopButton_sjWU" type="button"></button><div class="docRoot_UBD9"><aside class="theme-doc-sidebar-container docSidebarContainer_YfHR"><div class="sidebarViewport_aRkj"><div class="sidebar_njMd"><nav aria-label="Docs sidebar" class="menu thin-scrollbar menu_SIkG"><ul class="theme-doc-sidebar-menu menu__list"><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-1 menu__list-item"><a class="menu__link" href="../../index.html">Introduction</a></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-0/intro.html">Contents and Figures</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-1/b-b-scope-purpose-and-history.html">1. Introduction</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-2/c-b-character-syntax.html">2. Syntax</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-3/d-b-evaluation.html">3. Evaluation and Compilation</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-4/e-b-introduction.html">4. Types and Classes</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-5/f-b-generalized-reference.html">5. Data and Control Flow</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-6/g-b-the-loop-facility.html">6. Iteration</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-7/h-b-object-creation-and-initialization.html">7. Objects</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../category/81-structures-dictionary.html">8. Structures</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-9/j-b-condition-system-concepts.html">9. Conditions</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret menu__link--active" aria-expanded="true" href="../ba-b-symbol-concepts.html">10. Symbols</a></div><ul style="display:block;overflow:visible;height:auto" class="menu__list"><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="../ba-b-symbol-concepts.html">10.1 Symbol Concepts</a></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-2 menu__list-item"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--active" aria-expanded="true" tabindex="0" href="../../category/102-symbols-dictionary.html">10.2 Symbols Dictionary</a><button aria-label="Collapse sidebar category '10.2 Symbols Dictionary'" type="button" class="clean-btn menu__caret"></button></div><ul style="display:block;overflow:visible;height:auto" class="menu__list"><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="boundp_function.html">boundp</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="copy-symbol_function.html">copy-symbol</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="gensym-counter_variable.html">gensym-counter</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="gensym_function.html">gensym</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="gentemp_function.html">gentemp</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="get_accessor.html">get</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="keyword_type.html">keyword</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="keywordp_function.html">keywordp</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="make-symbol_function.html">make-symbol</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="makunbound_function.html">makunbound</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="remprop_function.html">remprop</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="set_function.html">set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="symbol-function_accessor.html">symbol-function</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="symbol-name_function.html">symbol-name</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="symbol-package_function.html">symbol-package</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="symbol-plist_accessor.html">symbol-plist</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="symbol-value_accessor.html">symbol-value</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link menu__link--active" aria-current="page" tabindex="0" href="symbol_system-class.html">symbol</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="symbolp_function.html">symbolp</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-3 menu__list-item"><a class="menu__link" tabindex="0" href="unbound-variable_condition-type.html">unbound-variable</a></li></ul></li></ul></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-11/bb-b-package-concepts.html">11. Packages</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-12/bc-b-number-concepts.html">12. Numbers</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-13/bd-b-character-concepts.html">13. Characters</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-14/be-b-cons-concepts.html">14. Conses</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-15/bf-b-array-concepts.html">15. Arrays</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-16/bg-b-string-concepts.html">16. Strings</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-17/bh-b-sequence-concepts.html">17. Sequences</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-18/bi-b-hash-table-concepts.html">18. Hash Tables</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-19/bj-b-overview-of-filenames.html">19. Filenames</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-20/ca-b-file-system-concepts.html">20. Files</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-21/cb-b-stream-concepts.html">21. Streams</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-22/cc-b-the-lisp-printer.html">22. Printer</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-23/cd-b-reader-concepts.html">23. Reader</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-24/ce-b-system-construction-concepts.html">24. System Construction</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-25/cf-b-the-external-environment.html">25. External Environment</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../environments.html">26. Environments</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../meta-object-protocol.html">27. Meta Object Protocol</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../data-structures.html">28. Data Structures</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../portability/trivial-packages.html">29. Portability</a></div></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-1 menu__list-item"><a class="menu__link" href="../../dictionary-entries.html">dictionary-entries</a></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" aria-expanded="false" href="../../chap-26/intro.html">Glossary</a></div></li></ul></nav></div></div></aside><main class="docMainContainer_TBSr"><div class="container padding-top--md padding-bottom--lg"><div class="row"><div class="col docItemCol_VOVn"><div class="docItemContainer_Djhp"><article><nav class="theme-doc-breadcrumbs breadcrumbsContainer_Z_bl" aria-label="Breadcrumbs"><ul class="breadcrumbs" itemscope="" itemtype="https://schema.org/BreadcrumbList"><li class="breadcrumbs__item"><a aria-label="Home page" class="breadcrumbs__link" href="../../index.html"><svg viewBox="0 0 24 24" class="breadcrumbHomeIcon_YNFT"><path d="M10 19v-5h4v5c0 .55.45 1 1 1h3c.55 0 1-.45 1-1v-7h1.7c.46 0 .68-.57.33-.87L12.67 3.6c-.38-.34-.96-.34-1.34 0l-8.36 7.53c-.34.3-.13.87.33.87H5v7c0 .55.45 1 1 1h3c.55 0 1-.45 1-1z" fill="currentColor"></path></svg></a></li><li class="breadcrumbs__item"><span class="breadcrumbs__link">10. Symbols</span><meta itemprop="position" content="1"></li><li itemscope="" itemprop="itemListElement" itemtype="https://schema.org/ListItem" class="breadcrumbs__item"><a class="breadcrumbs__link" itemprop="item" href="../../category/102-symbols-dictionary.html"><span itemprop="name">10.2 Symbols Dictionary</span></a><meta itemprop="position" content="2"></li><li itemscope="" itemprop="itemListElement" itemtype="https://schema.org/ListItem" class="breadcrumbs__item breadcrumbs__item--active"><span class="breadcrumbs__link" itemprop="name">symbol</span><meta itemprop="position" content="3"></li></ul></nav><div class="tocCollapsible_ETCw theme-doc-toc-mobile tocMobile_ITEo"><button type="button" class="clean-btn tocCollapsibleButton_TO0P">On this page</button></div><div class="theme-doc-markdown markdown"><h1>symbol</h1>
|
||
<!-- -->
|
||
<!-- -->
|
||
<p><strong>symbol</strong> <span><i>System Class</i></span></p>
|
||
<p><strong>Class Precedence List:</strong></p>
|
||
<p><span><b>symbol</b></span>, <span><b>t</b></span></p>
|
||
<p><strong>Description:</strong></p>
|
||
<p><span><i>Symbols</i></span> are used for their <span><i>object</i></span> identity to name various entities in Common Lisp, including (but not limited to) linguistic entities such as <span><i>variables</i></span> and <span><i>functions</i></span>.</p>
|
||
<p><span><i>Symbols</i></span> can be collected together into <span><i>packages</i></span>. A <span><i>symbol</i></span> is said to be <span><i>interned</i></span> in a <span><i>package</i></span> if it is <span><i>accessible</i></span> in that <span><i>package</i></span>; the same <span><i>symbol</i></span> can be <span><i>interned</i></span> in more than one <span><i>package</i></span>. If a <span><i>symbol</i></span> is not <span><i>interned</i></span> in any <span><i>package</i></span>, it is called <span><i>uninterned</i></span>.</p>
|
||
<p>An <em>interned symbol</em> is uniquely identifiable by its <span><i>name</i></span> from any <span><i>package</i></span> in which it is <span><i>accessible</i></span>.</p>
|
||
<p><span><i>Symbols</i></span> have the following attributes. For historical reasons, these are sometimes referred to as <span><i>cells</i></span>, although the actual internal representation of <span><i>symbols</i></span> and their attributes is <span><i>implementation-dependent</i></span>.</p>
|
||
<p><strong>Name</strong></p>
|
||
<p>The <span><i>name</i></span> of a <span><i>symbol</i></span> is a <span><i>string</i></span> used to identify the <span><i>symbol</i></span>. Every <span><i>symbol</i></span> has a <span><i>name</i></span>, and the consequences are undefined if that <span><i>name</i></span> is altered. The <span><i>name</i></span> is used as part of the external, printed representation of the <span><i>symbol</i></span>; see Section 2.1 (Character Syntax). The <span><i>function</i></span> <span><b>symbol-name</b></span> returns the <span><i>name</i></span> of a given <span><i>symbol</i></span>. A <span><i>symbol</i></span> may have any <span><i>character</i></span> in its <span><i>name</i></span>.</p>
|
||
<p><strong>Package</strong></p>
|
||
<p>The <span><i>object</i></span> in this <span><i>cell</i></span> is called the <span><i>home package</i></span> of the <span><i>symbol</i></span>. If the <span><i>home package</i></span> is <span><b>nil</b></span>, the <span><i>symbol</i></span> is sometimes said to have no <span><i>home package</i></span>.</p>
|
||
<p>When a <span><i>symbol</i></span> is first created, it has no <span><i>home package</i></span>. When it is first <span><i>interned</i></span>, the <span><i>package</i></span> in which it is initially <span><i>interned</i></span> becomes its <span><i>home package</i></span>. The <span><i>home package</i></span> of a <span><i>symbol</i></span> can be <em>accessed</em> by using the <span><i>function</i></span> <span><b>symbol-package</b></span>.</p>
|
||
<p>If a <span><i>symbol</i></span> is <span><i>uninterned</i></span> from the <span><i>package</i></span> which is its <span><i>home package</i></span>, its <span><i>home package</i></span> is set to <span><b>nil</b></span>. Depending on whether there is another <span><i>package</i></span> in which the <span><i>symbol</i></span> is <span><i>interned</i></span>, the symbol might or might not really be an <em>uninterned symbol</em>. A <span><i>symbol</i></span> with no <span><i>home package</i></span> is therefore called <span><i>apparently uninterned</i></span>.</p>
|
||
<p>The consequences are undefined if an attempt is made to alter the <span><i>home package</i></span> of a <span><i>symbol</i></span> external in the COMMON-LISP <span><i>package</i></span> or the KEYWORD <span><i>package</i></span>.</p>
|
||
<p><strong>Property list</strong></p>
|
||
<p>The <span><i>property list</i></span> of a <span><i>symbol</i></span> provides a mechanism for associating named attributes</p>
|
||
<p>with that <span><i>symbol</i></span>. The operations for adding and removing entries are <span><i>destructive</i></span> to the <span><i>property list</i></span>. Common Lisp provides <span><i>operators</i></span> both for direct manipulation of <em>property list objects</em> (<em>e.g.</em>, see <span><b>getf</b></span>, <span><b>remf</b></span>, and <span><b>symbol-plist</b></span>) and for implicit manipulation of a <span><i>symbol</i></span>’s <span><i>property list</i></span> by reference to the <span><i>symbol</i></span> (<em>e.g.</em>, see <span><b>get</b></span> and <span><b>remprop</b></span>). The <span><i>property list</i></span> associated with a <em>fresh symbol</em> is initially <span><i>null</i></span>.</p>
|
||
<p><strong>Value</strong></p>
|
||
<p>If a symbol has a value attribute, it is said to be <span><i>bound</i></span>, and that fact can be detected by the <span><i>function</i></span> <span><b>boundp</b></span>. The <span><i>object</i></span> contained in the <span><i>value cell</i></span> of a <em>bound symbol</em> is the <span><i>value</i></span> of the <span><i>global variable</i></span> named by that <span><i>symbol</i></span>, and can be <em>accessed</em> by the <span><i>function</i></span> <span><b>symbol-value</b></span>. A <span><i>symbol</i></span> can be made to be <span><i>unbound</i></span> by the <span><i>function</i></span> <span><b>makunbound</b></span>.</p>
|
||
<p>The consequences are undefined if an attempt is made to change the <span><i>value</i></span> of a <span><i>symbol</i></span> that names a <span><i>constant variable</i></span>, or to make such a <span><i>symbol</i></span> be <span><i>unbound</i></span>.</p>
|
||
<p><strong>Function</strong></p>
|
||
<p>If a symbol has a function attribute, it is said to be <span><i>fbound</i></span>, and that fact can be detected by the <span><i>function</i></span> <span><b>fboundp</b></span>. If the <span><i>symbol</i></span> is the <span><i>name</i></span> of a <span><i>function</i></span> in the <span><i>global environment</i></span>, the <span><i>function cell</i></span> contains the <span><i>function</i></span>, and can be <em>accessed</em> by the <span><i>function</i></span> <span><b>symbol-function</b></span>. If the <span><i>symbol</i></span> is the <span><i>name</i></span> of either a <span><i>macro</i></span> in the <span><i>global environment</i></span> (see <span><b>macro-function</b></span>) or a <span><i>special operator</i></span> (see <span><b>special-operator-p</b></span>), the <span><i>symbol</i></span> is <span><i>fbound</i></span>, and can be <em>accessed</em> by the <span><i>function</i></span> <span><b>symbol-function</b></span>, but the <span><i>object</i></span> which the <span><i>function cell</i></span> contains is of <em>implementation-dependent type</em> and purpose. A <span><i>symbol</i></span> can be made to be <span><i>funbound</i></span> by the <span><i>function</i></span> <span><b>fmakunbound</b></span>.</p>
|
||
<p>The consequences are undefined if an attempt is made to change the <span><i>functional value</i></span> of a <span><i>symbol</i></span> that names a <span><i>special form</i></span>.</p>
|
||
<p>Operations on a <span><i>symbol</i></span>’s <span><i>value cell</i></span> and <span><i>function cell</i></span> are sometimes described in terms of their effect on the <span><i>symbol</i></span> itself, but the user should keep in mind that there is an intimate relationship between the contents of those <span><i>cells</i></span> and the <span><i>global variable</i></span> or global <span><i>function</i></span> definition, respectively.</p>
|
||
<p><span><i>Symbols</i></span> are used as identifiers for <span><i>lexical variables</i></span> and lexical <span><i>function</i></span> definitions, but in that role, only their <span><i>object</i></span> identity is significant. Common Lisp provides no operation on a <span><i>symbol</i></span> that can have any effect on a <span><i>lexical variable</i></span> or on a lexical <span><i>function</i></span> definition.</p>
|
||
<p><strong>See Also:</strong></p>
|
||
<p>Section 2.3.4 (Symbols as Tokens), Section 2.3.1.1 (Potential Numbers as Tokens), Section 22.1.3.3 (Printing Symbols)</p>
|
||
<h2 class="anchor anchorWithStickyNavbar_LWe7" id="expanded-reference-symbol">Expanded Reference: symbol<a href="symbol_system-class.html#expanded-reference-symbol" class="hash-link" aria-label="Direct link to Expanded Reference: symbol" title="Direct link to Expanded Reference: symbol"></a></h2>
|
||
<div class="theme-admonition theme-admonition-tip admonition_xJq3 alert alert--success"><div class="admonitionHeading_Gvgb"><span class="admonitionIcon_Rf37"><svg viewBox="0 0 12 16"><path fill-rule="evenodd" d="M6.5 0C3.48 0 1 2.19 1 5c0 .92.55 2.25 1 3 1.34 2.25 1.78 2.78 2 4v1h5v-1c.22-1.22.66-1.75 2-4 .45-.75 1-2.08 1-3 0-2.81-2.48-5-5.5-5zm3.64 7.48c-.25.44-.47.8-.67 1.11-.86 1.41-1.25 2.06-1.45 3.23-.02.05-.02.11-.02.17H5c0-.06 0-.13-.02-.17-.2-1.17-.59-1.83-1.45-3.23-.2-.31-.42-.67-.67-1.11C2.44 6.78 2 5.65 2 5c0-2.2 2.02-4 4.5-4 1.22 0 2.36.42 3.22 1.19C10.55 2.94 11 3.94 11 5c0 .66-.44 1.78-.86 2.48zM4 14h5c-.23 1.14-1.3 2-2.5 2s-2.27-.86-2.5-2z"></path></svg></span>tip</div><div class="admonitionContent_BuS1"><p>TODO: Please contribute to this page by adding explanations and examples</p></div></div>
|
||
<div class="language-lisp codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-lisp codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#393A34"><span class="token punctuation" style="color:#393A34">(</span><span class="token car">symbol</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div></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/chap-10/ba-c-dictionary/symbol_system-class.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="symbol-value_accessor.html"><div class="pagination-nav__sublabel">Previous</div><div class="pagination-nav__label">symbol-value</div></a><a class="pagination-nav__link pagination-nav__link--next" href="symbolp_function.html"><div class="pagination-nav__sublabel">Next</div><div class="pagination-nav__label">symbolp</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="symbol_system-class.html#expanded-reference-symbol" class="table-of-contents__link toc-highlight">Expanded Reference: symbol</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_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://irclog.tymoon.eu/libera/commonlisp" target="_blank" rel="noopener noreferrer" class="footer__link-item">IRC<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></ul></div><div class="col footer__col"><div class="footer__title">More</div><ul class="footer__items clean-list"><li class="footer__item"><a href="../../../blog.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">Blog</a></li><li class="footer__item"><a href="https://github.com/lisp-docs/lisp-docs.github.io" target="_blank" rel="noopener noreferrer" class="footer__link-item">Tutorial and General Content 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></li><li class="footer__item"><a href="https://github.com/lisp-docs/cl-language-reference/" target="_blank" rel="noopener noreferrer" class="footer__link-item">Technical Reference 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></li><li class="footer__item"><a href="../../../docs/contribute.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">Contribute to the Docs</a></li></ul></div><div class="col footer__col"><div class="footer__title">Common Lisp Docs</div><ul class="footer__items clean-list"><li class="footer__item"><a href="../../../docs/about.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">About</a></li><li class="footer__item"><a href="../../../docs/whylisp.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">Why Lisp</a></li><li class="footer__item"><a href="../../../docs/getting-started.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">Getting Started</a></li><li class="footer__item"><a href="../../../docs/faq.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">FAQ</a></li><li class="footer__item"><a href="../../../docs/help.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">Getting Help</a></li><li class="footer__item"><a href="../../../docs/howto.html" target="_blank" rel="noopener noreferrer" class="footer__link-item">How To Guides</a></li></ul></div></div><div class="footer__bottom text--center"><div class="footer__copyright">Copyright © 2024 Common Lisp Docs, MIT License (see GitHub Repo).</div></div></div></footer></div>
|
||
</body>
|
||
</html> |