46 lines
36 KiB
HTML
46 lines
36 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-19/bj-b-overview-of-filenames" data-has-hydrated="false">
|
|||
|
|
<head>
|
|||
|
|
<meta charset="UTF-8">
|
|||
|
|
<meta name="generator" content="Docusaurus v3.0.1">
|
|||
|
|
<title data-rh="true">19.1 Overview of Filenames | 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-19/bj-b-overview-of-filenames"><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="19.1 Overview of Filenames | Common Lisp (New) Language Reference"><meta data-rh="true" name="description" content="19.1.1 Namestrings as Filenames"><meta data-rh="true" property="og:description" content="19.1.1 Namestrings as Filenames"><link data-rh="true" rel="icon" href="../img/favicon.ico"><link data-rh="true" rel="canonical" href="bj-b-overview-of-filenames.html"><link data-rh="true" rel="alternate" href="bj-b-overview-of-filenames.html" hreflang="en"><link data-rh="true" rel="alternate" href="bj-b-overview-of-filenames.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="bj-b-overview-of-filenames.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.
|
|||
|
|
<!-- -->
|
|||
|
|
<p>There are many kinds of <span><i>file systems</i></span>, varying widely both in their superficial syntactic details, and in their underlying power and structure. The facilities provided by Common Lisp for referring to and manipulating <span><i>files</i></span> has been chosen to be compatible with many kinds of <span><i>file systems</i></span>, while at the same time minimizing the program-visible differences between kinds of <span><i>file systems</i></span>.</p>
|
|||
|
|
<p>Since <span><i>file systems</i></span> vary in their conventions for naming <span><i>files</i></span>, there are two distinct ways to represent <span><i>filenames</i></span>: as <span><i>namestrings</i></span> and as <span><i>pathnames</i></span>.</p>
|
|||
|
|
<h2 class="anchor anchorWithStickyNavbar_LWe7" id="1911-namestrings-as-filenames">19.1.1 Namestrings as Filenames<a href="bj-b-overview-of-filenames.html#1911-namestrings-as-filenames" class="hash-link" aria-label="Direct link to 19.1.1 Namestrings as Filenames" title="Direct link to 19.1.1 Namestrings as Filenames"></a></h2>
|
|||
|
|
<!-- -->
|
|||
|
|
<p>A <span><i>namestring</i></span> is a <span><i>string</i></span> that represents a <span><i>filename</i></span>.</p>
|
|||
|
|
<p>In general, the syntax of <span><i>namestrings</i></span> involves the use of <span><i>implementation-defined</i></span> conventions, usually those customary for the <span><i>file system</i></span> in which the named <span><i>file</i></span> resides. The only exception is the syntax of a <em>logical pathname namestring</em>, which is defined in this specification; see Section 19.3.1 (Syntax of Logical Pathname Namestrings).</p>
|
|||
|
|
<p>A <span><i>conforming program</i></span> must never unconditionally use a <em>literal namestring</em> other than a <em>logical pathname namestring</em> because Common Lisp does not define any <span><i>namestring</i></span> syntax other than that for <span><i>logical pathnames</i></span> that would be guaranteed to be portable. However, a <span><i>conforming program</i></span> can, if it is careful, successfully manipulate user-supplied data which contains or refers to non-portable <span><i>namestrings</i></span>.</p>
|
|||
|
|
<p>A <span><i>namestring</i></span> can be <em>coerced</em> to a <span><i>pathname</i></span> by the <span><i>functions</i></span> <span><b>pathname</b></span> or <span><b>parse-namestring</b></span>.</p>
|
|||
|
|
<h2 class="anchor anchorWithStickyNavbar_LWe7" id="1912-pathnames-as-filenames">19.1.2 Pathnames as Filenames<a href="bj-b-overview-of-filenames.html#1912-pathnames-as-filenames" class="hash-link" aria-label="Direct link to 19.1.2 Pathnames as Filenames" title="Direct link to 19.1.2 Pathnames as Filenames"></a></h2>
|
|||
|
|
<!-- -->
|
|||
|
|
<p><span><i>Pathnames</i></span> are structured <span><i>objects</i></span> that can represent, in an <span><i>implementation-independent</i></span> way, the <span><i>filenames</i></span> that are used natively by an underlying <span><i>file system</i></span>.</p>
|
|||
|
|
<p>In addition, <span><i>pathnames</i></span> can also represent certain partially composed <span><i>filenames</i></span> for which an underlying <span><i>file system</i></span> might not have a specific <span><i>namestring</i></span> representation.</p>
|
|||
|
|
<p>A <span><i>pathname</i></span> need not correspond to any file that actually exists, and more than one <span><i>pathname</i></span> can refer to the same file. For example, the <span><i>pathname</i></span> with a version of <!-- -->:newest<!-- --> might refer to the same file as a <span><i>pathname</i></span> with the same components except a certain number as the version. Indeed, a <span><i>pathname</i></span> with version <!-- -->:newest<!-- --> might refer to different files as time passes, because the meaning of such a <span><i>pathname</i></span> depends on the state of the file system.</p>
|
|||
|
|
<p>Some <span><i>file systems</i></span> naturally use a structural model for their <span><i>filenames</i></span>, while others do not. Within the Common Lisp <span><i>pathname</i></span> model, all <span><i>filenames</i></span> are seen as having a particular structure, even if that structure is not reflected in the underlying <span><i>file system</i></span>. The nature of the mapping between structure imposed by <span><i>pathnames</i></span> and the structure, if any, that is used by the underlying <span><i>file system</i></span> is <span><i>implementation-defined</i></span>.</p>
|
|||
|
|
<p>Every <span><i>pathname</i></span> has six components: a host, a device, a directory, a name, a type, and a version. By naming <span><i>files</i></span> with <span><i>pathnames</i></span>, Common Lisp programs can work in essentially the same way even in <span><i>file systems</i></span> that seem superficially quite different. For a detailed description of these components, see Section 19.2.1 (Pathname Components).</p>
|
|||
|
|
<p>The mapping of the <span><i>pathname</i></span> components into the concepts peculiar to each <span><i>file system</i></span> is <span><i>implementation-defined</i></span>. There exist conceivable <span><i>pathnames</i></span> for which there is no mapping to a syntactically valid <span><i>filename</i></span> in a particular <span><i>implementation</i></span>. An <span><i>implementation</i></span> may use various strategies in an attempt to find a mapping; for example, an <span><i>implementation</i></span> may quietly truncate <span><i>filenames</i></span> that exceed length limitations imposed by the underlying <span><i>file system</i></span>, or ignore certain <span><i>pathname</i></span> components for which the <span><i>file system</i></span> provides no support. If such a mapping cannot be found, an error of <span><i>type</i></span> <span><b>file-error</b></span> is signaled.</p>
|
|||
|
|
<p>The time at which this mapping and associated error signaling occurs is <span><i>implementation-dependent</i></span>. Specifically, it may occur at the time the <span><i>pathname</i></span> is constructed, when coercing a <span><i>pathname</i></span> to a <span><i>namestring</i></span>, or when an attempt is made to <span><i>open</i></span> or otherwise access the <span><i>file</i></span> designated by the <span><i>pathname</i></span>.</p>
|
|||
|
|
<p>Figure 19–1 lists some <span><i>defined names</i></span> that are applicable to <span><i>pathnames</i></span>.</p>
|
|||
|
|
<p>|</p><p><strong>*default-pathname-defaults* namestring pathname-name directory-namestring open pathname-type enough-namestring parse-namestring pathname-version file-namestring pathname pathnamep file-string-length pathname-device translate-pathname host-namestring pathname-directory truename</strong> </p><p><strong>make-pathname pathname-host user-homedir-pathname merge-pathnames pathname-match-p wild-pathname-p</strong></p>|<p></p>
|
|||
|
|
<p>| :- |</p>
|
|||
|
|
<p><strong>Figure 19–1. Pathname Operations</strong></p>
|
|||
|
|
<h2 class="anchor anchorWithStickyNavbar_LWe7" id="1913-parsing-namestrings-into-pathnames">19.1.3 Parsing Namestrings Into Pathnames<a href="bj-b-overview-of-filenames.html#1913-parsing-namestrings-into-pathnames" class="hash-link" aria-label="Direct link to 19.1.3 Parsing Namestrings Into Pathnames" title="Direct link to 19.1.3 Parsing Namestrings Into Pathnames"></a></h2>
|
|||
|
|
<!-- -->
|
|||
|
|
<!-- -->
|
|||
|
|
<p>Parsing is the operation used to convert a <span><i>namestring</i></span> into a <span><i>pathname</i></span>. Except in the case of parsing <em>logical pathname namestrings</em>, this operation is <span><i>implementation-dependent</i></span>, because the format of <span><i>namestrings</i></span> is <span><i>implementation-dependent</i></span>.</p>
|
|||
|
|
<p>A <span><i>conforming implementation</i></span> is free to accommodate other <span><i>file system</i></span> features in its <span><i>pathname</i></span> representation and provides a parser that can process such specifications in <span><i>namestrings</i></span>. <span><i>Conforming programs</i></span> must not depend on any such features, since those features will not be portable.</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/chap-19/bj-b-overview-of-filenames.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="../chap-18/bi-c-dictionary/with-hash-table-iterator_macro.html"><div class="pagination-nav__sublabel">Previous</div><div class="pagination-nav__label">with-hash-table-iterator</div></a><a class="pagination-nav__link pagination-nav__link--next" href="bj-c-pathnames.html"><div class="pagination-nav__sublabel">Next</div><div class="pagination-nav__label">19.2 Pathnames</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="bj-b-overview-of-filenames.html#1911-namestrings-as-filenames" class="table-of-contents__link toc-highlight">19.1.1 Namestrings as Filenames</a></li><li><a href="bj-b-overview-of-filenames.html#1912-pathnames-as-filenames" class="table-of-contents__link toc-highlight">19.1.2 Pathnames as Filenames</a></li><li><a href="bj-b-overview-of-filenames.html#1913-parsing-namestrings-into-pathnames" class="table-of-contents__link toc-highlight">19.1.3 Parsing Namestrings Into Pathnames</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
|
|||
|
|
</body>
|
|||
|
|
</html>
|