ASTMult.java

public class ASTMult implements ASTNode {

        ASTNode lhs, rhs;
        
        public ASTMult(ASTNode l, ASTNode r) {
                lhs = l;
                rhs = r;
        }

        @Override
        public IValue eval(Environment<IValue> e) throws InterpreterError {
                IValue v1 = lhs.eval(e);
                IValue v2 = rhs.eval(e);
                if (v1 instanceof VInt && v2 instanceof VInt) {
                        int i1 = ((VInt) v1).getval();
                        int i2 = ((VInt) v2).getval();
                        return new VInt(i1 * i2);
                } else {
                        throw new InterpreterError("illegal types to * operator");
                }
        }

        @Override
        public ASTType typecheck(Environment<ASTType> e) throws TypeCheckError, InterpreterError {
                ASTType lhst = lhs.typecheck(e);
                ASTType rhst = rhs.typecheck(e);
                if (!(lhst instanceof ASTTInt) || !(rhst instanceof ASTTInt))
                        throw new TypeCheckError("*: arg type not int");
	        return ASTTInt.tint;
	}
        
        @Override
        public boolean isFreeOutsideLambda(String id) {
                return lhs.isFreeOutsideLambda(id) || rhs.isFreeOutsideLambda(id);
        }

}