code: public function acceptAttributeToken($token, $event)
      {
          if ($this->current_attribute) {
              if ($event == LEXER_UNMATCHED) {
                  $this->attributes[$this->current_attribute] .=
                          html_entity_decode($token, ENT_QUOTES);
              }
              if ($event == LEXER_SPECIAL) {
                  $this->attributes[$this->current_attribute] .=
                          preg_replace('/^=\s*/', '', html_entity_decode($token, ENT_QUOTES));
              }
          }
  
          return true;
      }
docs: Part of the tag data.
  
  @param string $token     Incoming characters.
  @param int $event    Lexer event type.
  
  @return bool          False if parse error.