code: protected function parse_whitespace() {
  		$this->token_start = $this->pos;
  
  		while(++$this->pos < $this->size) {
  			if (!isset($this->whitespace[$this->doc[$this->pos]])) {
  				break;
  			} else {
  				$this->parse_linebreak();
  			}
  		}
  
  		--$this->pos;
  		return self::TOK_WHITESPACE;
  	}
docs: Parse whitespace
  @return int Token
  @internal Gets called with {@link $whitespace} characters