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112 lines
3.2 KiB
XML
112 lines
3.2 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<!-- EN-Revision: 85050f5f88cca909b14b7cccc1dcedbb784a4fd6 Maintainer: mowangjuanzi Status: ready -->
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<reference xml:id="class.stringable" role="class" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xi="http://www.w3.org/2001/XInclude">
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<title>Stringable 接口</title>
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<titleabbrev>Stringable</titleabbrev>
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<partintro>
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<!-- {{{ Stringable intro -->
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<section xml:id="stringable.intro">
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&reftitle.intro;
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<para>
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<interfacename>Stringable</interfacename> 接口表示拥有
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<link linkend="object.tostring">__toString()</link> 方法的类。
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和大多数接口不同， <interfacename>Stringable</interfacename> 隐式存在于任何定义了
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<link linkend="object.tostring">__toString()</link> 魔术方法的类上，
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当然也可以显式声明它，并且推荐这么做。
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</para>
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<para>
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它的主要价值是能让函数针对简单的字符串或可以转化为字符串的对象，检测联合类型 <literal>string|Stringable</literal>。
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</para>
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</section>
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<!-- }}} -->
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<section xml:id="stringable.synopsis">
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&reftitle.interfacesynopsis;
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<!-- {{{ Synopsis -->
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<classsynopsis class="interface">
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<oointerface>
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<interfacename>Stringable</interfacename>
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</oointerface>
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<classsynopsisinfo role="comment">&Methods;</classsynopsisinfo>
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<xi:include xpointer="xmlns(db=http://docbook.org/ns/docbook) xpointer(id('class.stringable')/db:refentry/db:refsect1[@role='description']/descendant::db:methodsynopsis[@role='Stringable'])">
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<xi:fallback/>
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</xi:include>
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</classsynopsis>
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<!-- }}} -->
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</section>
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<section xml:id="stringable.examples">
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<title>Stringable 示例</title>
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<para>
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<example xml:id="stringable.basic-example">
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<title>基础 Stringable 用法</title>
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<simpara>这里使用了<link linkend="language.oop5.decon.constructor.promotion">构造器属性提升</link>。</simpara>
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<programlisting role="php">
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<![CDATA[
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<?php
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class IPv4Address implements Stringable {
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public function __construct(
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private string $oct1,
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private string $oct2,
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private string $oct3,
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private string $oct4,
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) {}
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public function __toString(): string {
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return "$this->oct1.$this->oct2.$this->oct3.$this->oct4";
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}
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}
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function showStuff(string|Stringable $value) {
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// 存在 Stringable，这将默认调用 __toString()。
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print $value;
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}
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$ip = new IPv4Address('123', '234', '42', '9');
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showStuff($ip);
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?>
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]]>
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</programlisting>
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&example.outputs.similar;
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<screen>
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<![CDATA[
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123.234.42.9
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]]>
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</screen>
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</example>
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</para>
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</section>
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</partintro>
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&language.predefined.stringable.tostring;
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</reference>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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