if语句中放一个#define

开发一个iPhone应用，需要做宽屏检测，用到许多#define，想要放到if语句中，不知道怎么实现。

// Device and Widescreen Detection
#define IS_WIDESCREEN ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )568 ) < DBL_EPSILON )

// iPhone
#define IS_IPHONE ( [ [ [ UIDevice currentDevice ] model ] isEqualToString: @"iPhone" ] )  || ( [ [ [ UIDevice currentDevice ] model ] isEqualToString: @"iPhone Simulator" ] ) )
#define IS_IPHONE_5 ( IS_IPHONE && IS_WIDESCREEN )

// iPod Touch
#define IS_IPOD   ( [ [ [ UIDevice currentDevice ] model ] isEqualToString: @"iPod touch" ] )
#define IS_IPOD_5 ( IS_IPOD && IS_WIDESCREEN )

// iPad
#define IS_IPAD (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)

if语句：

if (IS_IPHONE_5) {
...
} else {
...
}

遇到的问题：if语句会返回错误：

if (IS_IPHONE_5 {
...
} else {
...
}

或者：

if IS_IPHONE_5 {
...
} else {
...
}

为什么会报错？应该怎么正确实现?

#define IS_IPHONE ( [ [ [ UIDevice currentDevice ] model ] isEqualToString: @"iPhone" ] ) || ( [ [ [ UIDevice currentDevice ] model ] isEqualToString: @"iPhone Simulator" ] )

最后的地方多了个括号啊！！！！！！！！

**可以考虑用 条件编译 加 宏编译，
#if IS_IPHONE_5
. . .
#elif 条件
. . .
#else
. . .
#endif