Method typeCheck

src/chap14/TypeChecker.java:107–118

(TypeEnv tenv)

    @Reviser public static class IfEx extends IfStmnt {
        public IfEx(List<ASTree> c) { super(c); }
        public TypeInfo typeCheck(TypeEnv tenv) throws TypeException {
            TypeInfo condType = ((ASTreeTypeEx)condition()).typeCheck(tenv);
            condType.assertSubtypeOf(TypeInfo.INT, tenv, this);
            TypeInfo thenType = ((ASTreeTypeEx)thenBlock()).typeCheck(tenv);
            TypeInfo elseType;
            ASTree elseBk = elseBlock();
            if (elseBk == null)
                elseType = TypeInfo.INT; 
            else
                elseType = ((ASTreeTypeEx)elseBk).typeCheck(tenv);
            return thenType.union(elseType, tenv);
        }
    }
    @Reviser public static class WhileEx extends WhileStmnt {
        public WhileEx(List<ASTree> c) { super(c); }