Assignment 2

Due on Feb 10 before lecture.

Email your solutions to bchandra@eecs.umich.edu. Preferably, email them as an attachment, with the filename: your_unique_name.zip

Problem 1a

Consider the language of Featherweight Java discussed in class (Figures 1, 2, 3 in the Featherweight Java paper). Your goal for this project is to implement a type checker for Featherweight Java.

A partial implementation of a type checker is available from below:

fj.zip

The README file describes how to build Featherweight Java.

Note that several methods of the type checker are not yet implemented properly. These include the following:

fj.types.ClassTable.override
fj.types.ClassTable.subtype
fj.typecheck.TypeChecker.checkProgram
fj.typecheck.TypeChecker.checkMethod
fj.typecheck.TypeChecker.checkVarTerm
fj.typecheck.TypeChecker.checkFieldTerm
fj.typecheck.TypeChecker.checkCallTerm
fj.typecheck.TypeChecker.checkNewTerm
fj.typecheck.TypeChecker.checkCastTerm

Implement the above methods to complete the implementation of a type checker for Featherweight Java. Please submit the source code of your type checker.

Problem 1b

Your goal for this problem is to test your above type checker implementation. The tests directory supplied to you contains a bare minimal test suite. Write a more comprehensive test suite by writing both type-correct and type-incorrect example programs that thoroughly test your implementation. Please submit your test suite.