公共静态变量值

Question

我想声明一个公共静态变量是阵列的阵列：

class Foo{ 
public static $contexts = array(
    'a' => array(
     'aa'    => something('aa'), 
     'bb'    => something('bb'), 
    ), 

    'b' => array(
     'aa'    => something('aa'), 
     'bb'    => something('bb'), 
    ), 

); 

// methods here 

} 

function something($s){ 
    return ... 
} 

但我得到一个错误：

Parse error: parse error, expecting `')'' in ...

Answer 1

你不能使用表达式当声明类属性时。即您不能在这里拨打something()，您只能使用静态值。您必须在某些时候以不同的代码设置这些值。

Like any other PHP static variable, static properties may only be initialized using a literal or constant; expressions are not allowed. So while you may initialize a static property to an integer or array (for instance), you may not initialize it to another variable, to a function return value, or to an object.

http://www.php.net/manual/en/language.oop5.static.php

例如：

class Foo { 
    public static $bar = null; 

    public static function init() { 
     self::$bar = array(...); 
    } 
} 

Foo::init(); 

或做它__construct，如果你打算将类实例。