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117 lines
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HTML
117 lines
7.3 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>检测参数是否为合法的可调用结构</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.is-callable" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">is_callable</h1>
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<p class="verinfo">(PHP 4 >= 4.0.6, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">is_callable</span> — <span class="dc-title">
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检测参数是否为合法的可调用结构
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</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.is-callable-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>is_callable</strong></span>
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( <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$name</code></span>
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[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$syntax_only</code><span class="initializer"> = false</span></span>
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[, <span class="methodparam"><span class="type">string</span> <code class="parameter reference">&$callable_name</code></span>
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]] ) : <span class="type">bool</span></div>
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<p class="para rdfs-comment">
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验证变量的内容能否作为函数调用。
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这可以检查包含有效函数名的变量，或者一个数组，包含了正确编码的对象以及函数名。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.is-callable-parameters">
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<h3 class="title">参数</h3>
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<p class="para">
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<dl>
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<dt>
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<code class="parameter">name</code></dt>
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<dd>
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<p class="para">
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要检查的回调函数。
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</p>
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</dd>
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<dt>
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<code class="parameter">syntax_only</code></dt>
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<dd>
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<p class="para">
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如果设置为 <strong><code>TRUE</code></strong>，这个函数仅仅验证 <code class="parameter">name</code> 可能是函数或方法。
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它仅仅拒绝非字符，或者未包含能用于回调函数的有效结构。有效的应该包含两个元素，第一个是一个对象或者字符，第二个元素是个字符。
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</p>
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</dd>
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<dt>
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<code class="parameter">callable_name</code></dt>
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<dd>
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<p class="para">
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接受“可调用的名称”。下面的例子是“someClass::someMethod”。
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注意，尽管 someClass::SomeMethod() 的含义是可调用的静态方法，但例子的情况并不是这样的。
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</p>
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</dd>
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</dl>
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</p>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.is-callable-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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如果 <code class="parameter">name</code> 可调用则返回 <strong><code>TRUE</code></strong>，否则返回 <strong><code>FALSE</code></strong>。
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.is-callable-examples">
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<h3 class="title">范例</h3>
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<p class="para">
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<div class="example" id="example-6362">
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<p><strong>Example #1 <span class="function"><strong>is_callable()</strong></span> 例子</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// How to check a variable to see if it can be called<br />// as a function.<br /><br />//<br />// Simple variable containing a function<br />//<br /><br /></span><span style="color: #007700">function </span><span style="color: #0000BB">someFunction</span><span style="color: #007700">() <br />{<br />}<br /><br /></span><span style="color: #0000BB">$functionVariable </span><span style="color: #007700">= </span><span style="color: #DD0000">'someFunction'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">is_callable</span><span style="color: #007700">(</span><span style="color: #0000BB">$functionVariable</span><span style="color: #007700">, </span><span style="color: #0000BB">false</span><span style="color: #007700">, </span><span style="color: #0000BB">$callable_name</span><span style="color: #007700">)); </span><span style="color: #FF8000">// bool(true)<br /><br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">$callable_name</span><span style="color: #007700">, </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">; </span><span style="color: #FF8000">// someFunction<br /><br />//<br />// Array containing a method<br />//<br /><br /></span><span style="color: #007700">class </span><span style="color: #0000BB">someClass </span><span style="color: #007700">{<br /><br /> function </span><span style="color: #0000BB">someMethod</span><span style="color: #007700">() <br /> {<br /> }<br /><br />}<br /><br /></span><span style="color: #0000BB">$anObject </span><span style="color: #007700">= new </span><span style="color: #0000BB">someClass</span><span style="color: #007700">();<br /><br /></span><span style="color: #0000BB">$methodVariable </span><span style="color: #007700">= array(</span><span style="color: #0000BB">$anObject</span><span style="color: #007700">, </span><span style="color: #DD0000">'someMethod'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">is_callable</span><span style="color: #007700">(</span><span style="color: #0000BB">$methodVariable</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">, </span><span style="color: #0000BB">$callable_name</span><span style="color: #007700">)); </span><span style="color: #FF8000">// bool(true)<br /><br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">$callable_name</span><span style="color: #007700">, </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">; </span><span style="color: #FF8000">// someClass::someMethod<br /><br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.is-callable-seealso">
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<h3 class="title">参见</h3>
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<p class="para">
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<ul class="simplelist">
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<li class="member"><span class="function"><a href="function_exists.html" class="function" rel="rdfs-seeAlso">function_exists()</a> - 如果给定的函数已经被定义就返回 TRUE</span></li>
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<li class="member"><span class="function"><a href="method_exists.html" class="function" rel="rdfs-seeAlso">method_exists()</a> - 检查类的方法是否存在</span></li>
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</ul>
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</p>
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</div>
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</div></div></div></body></html> |