code: private void parseOrExpr() throws TTXPathException {
  
          parseAndExpr();
  
          while (is("or", true)) {
  
              mPipeBuilder.addExpressionSingle();
  
              parseAndExpr();
              mPipeBuilder.addOrExpression(getTransaction());
  
          }
      }
docs: Parses the the rule OrExpr according to the following production rule:
  <p>
  [8] OrExpr ::= AndExpr ( "or" AndExpr )* .
  </p>
  
  @throws TTXPathException