original_string: public function touch($key, $expiration = 0) {
      $result = $this->get($key, null, $cas_token);
      if ($result) {
        $result = $this->cas($cas_token, $key, $result, $expiration);
      }
      $this->result_code = $result ? self::RES_SUCCESS : self::RES_FAILURE;
      return $result;
    }
code: public function touch($key, $expiration = 0) {
      $result = $this->get($key, null, $cas_token);
      if ($result) {
        $result = $this->cas($cas_token, $key, $result, $expiration);
      }
      $this->result_code = $result ? self::RES_SUCCESS : self::RES_FAILURE;
      return $result;
    }
code_tokens: public function touch ( $ key , $ expiration = 0 ) { $ result = $ this -> get ( $ key , null , $ cas_token ) ; if ( $ result ) { $ result = $ this -> cas ( $ cas_token , $ key , $ result , $ expiration ) ; } $ this -> result_code = $ result ? self :: RES_SUCCESS : self :: RES_FAILURE ; return $ result ; }
docstring: Sets a new expiration time on an item.
  
  @param string $key The key under which to append the value.
  @param int $expiration The expiration time, defaults to 0.
  
  @return bool true on success or false on failure.
docstring_tokens: Sets a new expiration time on an item .