为什么在php类中作为数组项不起作用 [英] Why function as array item in php class doesn't work

问题描述

例如，我有这样一个代码：

 <？php 
 $ A = array（
'echoSmth'=> function（）{
 echo'Smth'; 
} 
）; 
 
 $ A ['echoSmth']（）; //'Smth'
？> 
  

工作正常！
但是如果$ A不仅仅是一个变量，而是一个Class方法 - 比这不行：

  <？php 
 
 class AA {
 
 public $ A = array（
'echoSmth'=> function（）{//解析错误！ b $ b echo'Smth'; 
} 
）; 
 
} 
 
 //固定呼叫：
 $ t = new AA（）; 
 $ t-> A ['echoSmth']（）; 
 //不管是什么调用，因为错误发生得早 - 在描述类
 
？> 
  

为什么它不起作用？
它显示：
解析错误：语法错误，意外的T_FUNCTION

对不起，我用我称呼该方法的方式犯了一些错误，我很着急。但不管我怎么打电话。错误ocurrs，即使我只是声明类，而不调用 解决方案

据我所知，你不能有任何东西动态定义类成员时，可以按照以下方式动态设置它。所以基本上，你不能这样做，因为你不能这样做： public $ A = functionname（）;

另外，您的通话签名不正确，我已经在我的示例中修复了它。

 < ？php 
 class AA {
 public $ A = array（）; 
 
 public function __construct（）{
 $ a = function（）{
 echo'Smth'; 
}; 
 $ this-> A ['echoSmth'] = $ a; 
} 
} 
 
 $ t = new AA（）; 
 $ t-> A ['echoSmth']（）; 
  

或者，您可以在 __ construct（），包含该方法（所以基本上转移你的代码）。

For example, I have such a code:

<?php
$A = array(
    'echoSmth' => function(){ 
        echo 'Smth';
    }
);

$A['echoSmth']();  // 'Smth'
?>

It works fine! But If $A is not just a variable, but a Class method - than this doesn't work:

<?php

class AA {

    public $A = array(
        'echoSmth' => function(){ // Parse Error here!
            echo 'Smth';
        }
    );

}

// Fixed call:
$t = new AA();
$t->A['echoSmth']();
// no matter what call, because error occurs early - in describing of class

?>

Why doesn't it work? It displays: Parse error: syntax error, unexpected T_FUNCTION

P.S. Sorry, I've made some mistakes in the way I call the method, I was in hurry. But there's no matter how I call. Error ocurrs even if I just declare class, without calling

解决方案

As far as I'm aware, you can't have anything dynamic when defining a class member, you can however set it dynamically as below. So basically, you can't do it for the same reason that you can't do this: public $A = functionname();

Also, your call signature was incorrect, I've fixed it in my example.

<?php
class AA {
    public $A = array();

    public function __construct() {
        $a = function() {
            echo 'Smth';
        };
        $this->A['echoSmth'] = $a;
    }
}

$t = new AA();
$t->A['echoSmth']();

Alternatively, you could define the whole array within __construct(), containing the method (so basically shift your code).

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