如何创建“或”开关使用typedef枚举？ [英] How do I create "or'ed" switches using typedef enum?

问题描述

我有点像枚举。他们的语法是神秘的，我还没有找到一个确定的参考点，他们无可否认地正确使用..但让我们说我有..

I kinda like enums. Their syntax is arcane-looking, and I've yet to find a definitive point of reference on their undeniably proper use.. but let's say I had..

typedef enum {
    OrientTop,
    OrientBottom,
    OrientFiesta
}   Orient;

我喜欢像我一样，像多个选择可能适用/需要，只是做...

I'd love to be able, as I do with, for example, other constants when multiple chocies may be applicable/ required, just do…

 self.orientation = OrientTop | OrientFiesta;  // NO NO WORK-O!

就像一个人一样...

just like one does with…

self.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable;

还是..

it = [[NSThing alloc]initOptions: NSStupid | NSSpicy | NSSassy];

它也会很好..而不是...

and it would also be nice.. instead of…

 if ((o == OrientTop ) || ( o == OrientBottom))

我只能使用...

if (o == OrientTop || OrientBottom) 

最重要的是...如何检查多个案例，ála ..

switch (orientation) {
    case OrientTop | OrientBottom:

或类似的东西..
呃，你们太慢了..所以，我只需要...

Or something, of the sort.. ugh, oh.. you guys are too slow.. so, duh.. i just need to…

case OrientLeft:
case OrientRight:  { // blah blah blah
     break;        }

（但是第一部分..）苹果/比我更聪明的人...正在使用他们的 typedef 的额外的zing，使我的味道这样，ech..bland ..相比之下

(But for the first part.. ) What is the extra "secret sauce" that Apple / smarter people than me.. are using to give their typedef's that extra zing that make mine taste so, ech..bland.. in comparison?

推荐答案

看起来好像 typedef 如 NSViewWidthSizable 实际上是bitmasks，这允许你喜欢的很好的ORing操作。在 UIKit 元素的标题中，您可以看到我的意思：

It appears as if typedefs such as NSViewWidthSizable are actually bitmasks, which allow the nice ORing operations you so enjoy. In the headers for some UIKit elements, you can see what I mean:

enum {
    UIViewAutoresizingNone                 = 0,
    UIViewAutoresizingFlexibleLeftMargin   = 1 << 0,
    UIViewAutoresizingFlexibleWidth        = 1 << 1,
    UIViewAutoresizingFlexibleRightMargin  = 1 << 2,
    UIViewAutoresizingFlexibleTopMargin    = 1 << 3,
    UIViewAutoresizingFlexibleHeight       = 1 << 4,
    UIViewAutoresizingFlexibleBottomMargin = 1 << 5
};
typedef NSUInteger UIViewAutoresizing;

我从非常有用的网站，更详细的解释，但你也可以通过保持命令⌘来检查任何常数的枚举，单击常量或typedef。

I snatched that right off a very helpful site that explains in more detail, but you can also examine the enumeration of any constant by holding Command ⌘ and clicking the constant or typedef.

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