douyi2798
2015-06-15 19:32
浏览 330
已采纳

你如何在PHP中的类中使用匿名函数?

How do I call $greet inside this class? I am using PHP 5.5.4.

<?PHP   
class Model
{
    public $greet = function($name)
    {
        printf("Hello %s
", $name);
    };
}

$test = new Model();
$test->greet('World');
$test->greet('PHP');
?>

Parse error: syntax error, unexpected '$greet' (T_VARIABLE), expecting function (T_FUNCTION)

Also tried this,

$test = new Model();
call_user_func($test->greet('World'));
call_user_func($test->greet('PHP')) 

The anonymous function works fine outside the class (straight from the manual).

<?php
$greet = function($name)
{
    printf("Hello %s
", $name);
};

$greet('World');
$greet('PHP');
?>

EDIT: I took out the dollar signs, in my call (I caught it just as an answer started to roll in. It did not help,

call_user_func($test->greet('World'));
call_user_func($test->greet('PHP'));

EDIT:

class Model
{
    public $greet;
    function __construct()
    {
        $this->greet = function($name)
        {
            printf("Hello %s
", $name);
        };
    }
}

$test = new Model();
$test->greet('johnny');

Now I get,

Fatal error: Call to undefined method Model::greet() 

图片转代码服务由CSDN问答提供 功能建议

如何在此课程中调用 $ greet ? 我使用的是PHP 5.5.4。

 &lt;?PHP 
class Model 
 {
 public $ greet = function($ name)
 {
 printf(  “Hello%s 
 
”,$ name); 
}; 
} 
 
 $ test = new Model(); 
 $ test-&gt; greet('World'); 
 $  test-&gt; greet('PHP'); 
?&gt; 
 
解析错误:语法错误,意外'$ greet'(T_VARIABLE),期待函数(T_FUNCTION)
   \  n 
 

也尝试了这个,

  $ test = new Model(); 
call_user_func($ test-&gt; greet('World')); 
call_user_func  ($ test-&gt; greet('PHP'))
   
 
 

匿名函数在类外工作正常(直接来自手册)。

 &lt;?php 
 $ greet  = function($ name)
 {
 printf(“Hello%s 
 
”,$ name); 
}; 
 
 $ greet('World'); 
 $ greet('PHP  '); 
?&gt; 
   
 
 

编辑:我在电话中取出了美元符号(我抓住它就像一个答案开始滚动。 它没有帮助,

  call_user_func($ test-&gt  ;迎接( '世界')); 
call_user_func($测试 - &GT;迎接( 'PHP')); 
   
 
 

编辑:

  class Model 
 {
 public $ greet; 
 function __construct()
 {
 $ this-&gt; greet = function($ name)
 {
 printf(“ 你好%s 
 
“,$ name); 
}; 
} 
} 
 
 $ test = new Model(); 
 $ test-&gt; greet('johnny'); \  n   
 
 

现在我明白了,

 致命错误:调用未定义的方法Model :: greet()
 <  / code>  
 
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2条回答 默认 最新

  • dongying6179 2015-06-15 21:03
    已采纳

    The fact that you call greet makes PHP treat it like a function and not a property. You can have the same name for both a property and method in PHP, so the distinction is relevant.

    What you can doe as a workaround is use the __call() magic method. It will catch the call to the undefined greet method.

    class Model
    {
        public $greet;
        function __construct()
        {
            $this->greet = function($name)
            {
                printf("Hello %s
    ", $name);
            };
        }
    
        function __call($method, $args)
        {
            if (isset($this->$method) && $this->$method instanceof \Closure) {
                return call_user_func_array($this->$method, $args);
            }
    
            trigger_error("Call to undefined method " . get_called_class() . '::' . $method, E_USER_ERROR);
        }
    }
    
    $test = new Model();
    $test->greet('johnny');
    

    Update for PHP7

    In PHP7 the __call() method is no longer needed to call closures bound to properties, because of Uniform Variable Syntax. This will allow you to add parentheses around any code, just like you do in arithmetics.

    class Model
    {
        public $greet;
        function __construct()
        {
            $this->greet = function($name)
            {
                printf("Hello %s
    ", $name);
            };
        }
    }
    
    $test = new Model();
    ($test->greet)('johnny');
    
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