code: private void parseComparisionExpr() throws TTXPathException {
  
          parseRangeExpr();
  
          final String mComp = mToken.getContent();
  
          if (isComp()) {
  
              // parse second operator axis
              mPipeBuilder.addExpressionSingle();
  
              parseRangeExpr();
  
              mPipeBuilder.addCompExpression(getTransaction(), mComp);
          }
  
      }
docs: Parses the the rule ComparisionExpr according to the following production
  rule:
  <p>
  [10] ComparisonExpr ::= RangeExpr ( (ValueComp | GeneralComp | NodeComp) RangeExpr )? .
  </p>
  
  @throws TTXPathException