How to use a Objective-C #define from Swift

At the moment, some #defines are converted and some aren't. More specifically:

#define A 1

...becomes:

var A: CInt { get }

Or:

#define B @"b"

...becomes:

var B: String { get }

Unfortunately, YES and NO aren't recognized and converted on the fly by the Swift compiler.

I suggest you convert your #defines to actual constants, which is better than #defines anyway.

.h:

extern NSString* const kSTRING_CONSTANT;
extern const BOOL kBOOL_CONSTANT;

.m

NSString* const kSTRING_CONSTANT = @"a_string_constant";
const BOOL kBOOL_CONSTANT = YES;

And then Swift will see:

var kSTRING_CONSTANT: NSString!
var kBOOL_CONSTANT: ObjCBool

Another option would be to change your BOOL defines to

#define kBOOL_CONSTANT 1

Faster. But not as good as actual constants.

Just a quick clarification on a few things from above.

Swift Constant are expressed using the keywordlet

For Example:

let kStringConstant:String = "a_string_constant"

Also, only in a protocol definition can you use { get }, example:

protocol MyExampleProtocol {
    var B:String { get }
}