Extended calculator

The code for this exercise is here

In the extended calculator, the Antlr grammar has been extended with statements to also handle simple expressions comparing values.

stmt : IF (comparison) THEN expression else expression |
       comparison | expr ;

The else-statement can be optional. Comparisons can the for normal binary operators.

Understanding the parser

Take 5 minutes to talk with a fellow student about what is needed to make this extension. You are welcome to try to implement it before looking at our implementation.

Traversing the parsing tree

THe file Interpreter.java` traverses the tree from Anltr.

In the method visitCompareStmt I have forgotten a couples of cases. Which are these? Add these to the file.

Look also at the visitStmt method and understand what it traverses.

Implementing execution

I have forgot to implement the execution of two of the binary operators. Implement these.

Testing

What will a good test look like. Extend the one there exists.