Section                       Program
Exercises 5.17, 5.18    You may choose to start with the software you developed in conjunction with Exercises 4.12 and
                                    4.13.  That is, expand the information provided in the implementations AbstractSyntax.java,
                                    StaticTypeCheck.java, and Semantics.java and use the drivers parser.java, typechecker.java, and
                                    interpreter.java to test your expansions.