php Exception打印error trace 实例

<?php
function x() $x = debug_backtrace();
//remove stack of this function
array_shift($x);
$i = 0;
$xstr = &#39;&#39;;
foreach ($trace as $x) {
    //TODO need check exists args
    $args = $x[&#39;args&#39;];
    if (!$args) {
        $argstr = &#39;&#39;;
    } else {
        $argstr = &#39;&#39;;
        $first = true;
        foreach ($args as $arg) {
            if (!$first) {
                $argstr.= &#39;,&#39;;
            }
            $first = false;
            if (is_object($arg)) {
                $argstr.= &#39;Object[&#39; . get_class($arg) . &#39;]&#39;;
            } elseif (is_array($arg)) {
                $argstr.= &#39;Array&#39;;
            } else {
                $argstr.= $arg;
            }
        }
    }
    $xstr.= "[#$i] {$x[&#39;file&#39;]}({$x[&#39;line&#39;]}) {$x[&#39;function&#39;]} ($argstr)" . PHP_EOL;
    $i++;
}
return $xstr;
}
?>