/* Original code */
(…)
//	local price = AIEngine.GetPrice(engine);
//	if (HasMoney(price)) GetMoney(price);
//	local vehicle = AIVehicle.BuildVehicle(best_hangar, engine);
//	RepayLoan();
//	if (!AIVehicle.IsValidVehicle(vehicle)) {
//		if (!silent_mode) AILog.Error("Couldn't build the aircraft");
//		return -1;
//	}
(…)


/* Modified code */
class BuildVehicleMoneyTest {
    function DoMoneyTest() {
	    if (WrightAI.HasMoney(GetPrice())) WrightAI.GetMoney(GetPrice());
	    if (DoBuildVehicle()) {
		    WrightAI.RepayLoan();
		    return true;
		}
	    WrightAI.RepayLoan();
		return false;
	}
}

class TestBuildVehicle extends BuildVehicleMoneyTest {
    h = null;
	e = null;
	v = null;
	p = null;
	
	function DoBuildVehicle() {
	    v = AIVehicle.BuildVehicle(h, e);
		if (!AIVehicle.IsValidVehicle(v)) {
//		    if (!silent_mode) AILog.Error("Couldn't build the aircraft");
		    return false;
		}
		return true;
	}
	
	function GetPrice() {
	    return AIEngine.GetPrice(e);
	}
	
	function TryBuild(best_hangar, engine) {
	    h = best_hangar;
		e = engine;
		p = GetPrice();
		if (DoMoneyTest()) {
		    return v;
		}
		return null;
	}
}

/* Somewhere else */
(…)
	local tvb = TestBuildVehicle();
	local vehicle = tvb.TryBuild(best_hangar, engine);
	if (vehicle == null) {
	    if (!silent_mode) AILog.Error("Couldn't build the aircraft");
		return -1;
	}
(…)