Open Radar

 
Summary:
I was in the process of answering https://lists.swift.org/pipermail/swift-users/Week-of-Mon-20160704/002488.html

Which fundamentally boils down to "I would like some things visible to Swift, and other things I can hide from it.

It's possible to do something like


Project-Bridging-Header.h

...
#define SUPPRESS_OLD_FOOD 1
#import "Foodies.h"


Foodies.h

typedef NS_OPTIONS(NSInteger, FoodType)
{
    FoodDairy = 1 << 0,
    FoodMeat = 1 << 1,
    FoodMushroom = 1 << 2,

#if !SUPPRESS_OLD_FOOD
// Old names
dairyFood = FoodDairy,
meatFood = FoodMeat,
mushroomFood = FoodMushroom
#endif
};


With the Bridging header, but Xcode doesn't seem to process "Generated Interface" by using the Bridging header (it shows the old and new names and doesn't simplify the Food* names), so now there's got two versions of the final generated header - the one Xcode will show you, and the one actually used by Swift.

I figure always using the Project-Bridging-Header.h when building the generated preview is a non-starter, just from a performance / general sanity point of view.

What I really want is a predefined macro that's only set during header generation that we can query to gate things like "this junk is purely for objective-C, it's better if Swift's generated headers doesn't even know it exists.