PHP 类中定义常量，并对常量的使用方法（转帖）

class MyClass{    const constant = 'constant value';    function showConstant() {        echo  self::constant . "\n";    }}echo MyClass::constant . "\n";$classname = "MyClass";echo $classname::constant . "\n"; // PHP 5.3.0之后$class = new MyClass();$class->showConstant();echo $class::constant."\n"; // PHP 5.3.0之后