code: @Override
      public int getDataType( CssFormatter formatter ) {
          if( type == UNKNOWN ) {
              switch( operator ) {
                  case ' ':
                  case ',':
                      type = LIST;
                      break;
                  case '&':
                  case '|':
                  case '>':
                  case '<':
                  case '=':
                  case '≥':
                  case '≤':
                      type = BOOLEAN;
                      break;
                  default:
                      type = maxOperadType( formatter );
              }
          }
          return type;
      }
docs: {@inheritDoc}