还原print_r($arr, TURE) 变成字串，如何还原

//还原print_r() 数组
$arr = array('C'=>'ccc', 'D'=>'ddd');
$p = print_r($arr,TRUE);
echo '<pre>';
var_dump($arr);
var_dump($p);
echo '</pre>';
如何还原？

 

//还原方法

class Trie {
  protected $dict = array();
  protected $buf = '';
  function set($word, $value='') {
    if(is_array($word)) foreach($word as $k=>$v) $this->set($k, $v);
    $p =& $this->dict;
    foreach(str_split($word) as $ch) {
        if(! isset($p[$ch])) $p[$ch] = array();
        $p =& $p[$ch];
    }
    $p['val'] = $value;
    return $this;
  }
  function parse($str) {
    $this->doc = $str;
    $this->len = strlen($str);
    $i = 0;
    while($i < $this->len) {
        $t = $this->find($this->dict, $i);
        if($t) {
            $i = $t;
            $this->buf = '';
        }else $this->buf .= $this->doc{$i++};
    }
  }
  protected function find(&$p, $i) {
    if($i >= $this->len) return $i;
    $t = 0;
    $n = $this->doc{$i};
    if( isset($p[$n]) ) $t = $this->find($p[$n], $i+1);
    if($t) return $t;
    if( isset($p['val']) ) {
        $ar = explode(',', $p['val']);
        call_user_func_array( array($this, array_shift($ar)), $ar );
        return $i;
    }
    return $t;
  }
  function __call($method, $param) {
    echo "****\n$this->buf 未定义方法:$method 参数:" . join(',', $param) . "<br />\n";
  }
}


class App extends Trie {
  public $res = array();
  protected $stack = array();
  protected $keyname = '';
  protected $buf = '';
  function __construct() {
    $this->stack[] =& $this->res;
  }
  protected function group() {
    if(! $this->keyname) return;
    $cnt = count($this->stack) - 1;
    $this->stack[$cnt][$this->keyname] = array();
    $this->stack[] =& $this->stack[$cnt][$this->keyname];
    $this->keyname = '';
  }
  protected function brackets($c) {
    $cnt = count($this->stack) - 1;
    switch($c) {
        case ')':
            if($this->keyname) $this->stack[$cnt][$this->keyname] = trim($this->buf);
            $this->keyname = '';
            array_pop($this->stack);
            break;
        case '[':
            if($this->keyname) $this->stack[$cnt][$this->keyname] = trim($this->buf);
            break;
        case ']':
            $this->keyname = $this->buf;
    }
    $this->buf = '';
  }
}


$arr=array('abcd'=>"sdfasdf",'bbb'=>'lxg','ccc'=>'bbbbbbbbb');
$ar = array('a'=>$arr, 'b'=>$arr);
$s = print_r($ar,true);
 
$p = new App;
$p -> set('Array', 'group') -> set(' [', 'brackets,[') -> set('] => ', 'brackets,]') -> set(')', 'brackets,)');
$p->parse($s);
print_r($p->res);