php – 如何回溯默认函数参数？

function backtrace() {
    var_dump(debug_backtrace());
}


function echosth($what = 'default text') {
    echo $what;
    backtrace();
}

echosth('another text'); //argument is shown 
                         // ["args"]=> array(1) {[0]=>&string(12) "another text"}
echosth(); //it appears as function has none arguments ["args"]=>array(0) {}

有没有办法获得父函数的默认值？

解决方法:

使用反射

http://php.net/manual/en/reflectionparameter.getdefaultvalue.php