public GenericValue getLeftAssociativeCalculation(final List<GenericValue> exprList,
final List<Operator> opList) {
if (exprList.size() == 1)
return exprList.get(0);
GenericValue root = new DelegateCalculation(exprList.get(0), opList.get(0), exprList.get(1));
for (int i = 1; i < opList.size(); i++)
root = new DelegateCalculation(root, opList.get(i), exprList.get(i + 1));
return root;
}