ASTGe.java

public class ASTGe implements ASTNode {
    ASTNode lhs, rhs;

    public ASTGe(ASTNode l, ASTNode r) {
        this.lhs = l;
        this.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 VBool(i1 >= i2);
		} else {
			throw new InterpreterError("illegal types to >= operator");
		}
    }

    @Override
    public ASTType typecheck(Environment<ASTType> e) throws TypeCheckError, InterpreterError {
        ASTType l = lhs.typecheck(e);
    	ASTType r = rhs.typecheck(e);
        if (!(l instanceof ASTTInt) || !(r instanceof ASTTInt))
            throw new TypeCheckError(">=: arg types not int");
        return ASTTBool.tbool;
    }

    @Override
    public boolean isFreeOutsideLambda(String id) {
        return lhs.isFreeOutsideLambda(id) || rhs.isFreeOutsideLambda(id);
    }

}