original_string: public function idArithmetic($action, array $options = array())
      {
          return $this->_idArithmetic($this->id, $action, array_merge(array(
              'count' => 1
          ), $options));
      }
code: public function idArithmetic($action, array $options = array())
      {
          return $this->_idArithmetic($this->id, $action, array_merge(array(
              'count' => 1
          ), $options));
      }
code_tokens: public function idArithmetic ( $ action , array $ options = array ( ) ) { return $ this -> _idArithmetic ( $ this -> id , $ action , array_merge ( array ( 'count' => 1 ) , $ options ) ) ; }
docstring: Performs MIME ID "arithmetic".
  
  @param string $action  One of:
  - ID_DOWN: ID of child. Note: ID_DOWN will first traverse to "$id.0"
  if given an ID *NOT* of the form "$id.0". If given an ID of
  the form "$id.0", ID_DOWN will traverse to "$id.1". This
  behavior can be avoided if 'no_rfc822' option is set.
  - ID_NEXT: ID of next sibling.
  - ID_PREV: ID of previous sibling.
  - ID_UP: ID of parent. Note: ID_UP will first traverse to "$id.0" if
  given an ID *NOT* of the form "$id.0". If given an ID of the
  form "$id.0", ID_UP will traverse to "$id". This behavior can
  be avoided if 'no_rfc822' option is set.
  @param array $options  Additional options:
  - count: (integer) How many levels to traverse.
  DEFAULT: 1
  - no_rfc822: (boolean) Don't traverse RFC 822 sub-levels.
  DEFAULT: false
  
  @return mixed  The resulting ID string, or null if that ID can not
  exist.
docstring_tokens: Performs MIME ID arithmetic .