php array 转代码格式的字符串

<?php
    class ArrayUtil
    {
        public static function array_to_string(array $source_array)
        {
            $r = '';
            self::a2s($r,$source_array);
            return $r;
        }
        //<editor-fold defaultstate="collapsed" desc="private method only for array_to_string">
        private static function a2s(&$r,array &$a)
        {
            $f = false;
            $i=0;
            $r.= 'array(';
            foreach ($a as $k=>$v)
            {
                if($f)
                    $r.=',';
                $j = is_numeric($k);
                self::o2s($r,$k,$v,$i,$j);
                $f=true;
                if($j && $k>=$i)
                    $i=$k+1;
            }
            $r.=')';
        }
        private static function o2s(&$r,$k,$v,$i,$j)
        {
            if($k!==$i)
            {
                if($j)
                    $r.="$k=>";
                else
                    $r.="'$k'=>";
            }
            if(is_array($v))
                self::a2s($r,$v);
            else if(is_numeric($v))
                $r.=$v;
            else
                $r.="'".str_replace(array("\\","'"),array("\\\\","\'"),$v)."'";
        }
        //</editor-fold>
    }
?>