Sum

• adder.g4
• adder.py

The program handles multiple lines of input when reading from a file. For example, given input, the command

        python adder.py input

prints

        Total: 6
        Total: 27
        Total: 55

There is a bug in version 4.5.3 of ANTLR that means that values are not propogated correctly in some recursive productions. This means the above adder.g4 file will crash on the sample input with a message about not being able to add to Nonetype. The fix is to introduce a new production; see rest_of_number_list in the file REVISED_adder.g4. Note you will need to save this file as adder.g4 to build (or change some of the other code to match this file).