void evalOp() {
	auto lab = Label(`.main.display`);

	if (curOp !is null) {
		lab.text = to!(char[])(curOp(prevNum, to!(long)(lab.text)));
		curOp = null;
	}

	enteringNewNum = true;
}


void onOp(long delegate(long a, long b) op) {
	evalOp();
	curOp = op;
	prevNum = to!(long)(Label(`.main.display`).text);
}