Objective-c categories with properties.

Something+Properties.h

// Objective-c categories with properties.
//
// Taken from:
// http://stackoverflow.com/a/22812632/667834
// http://stackoverflow.com/a/16020927/667834
// http://stackoverflow.com/a/11529511/667834
//

#define CATEGORY_PROPERTY_GET(type, property) \
    - (type) property { return objc_getAssociatedObject(self, @selector(property)); }
#define CATEGORY_PROPERTY_SET(type, property, setter) \
    - (void) setter (type) property { objc_setAssociatedObject(self, @selector(property), property, OBJC_ASSOCIATION_RETAIN_NONATOMIC); }
#define CATEGORY_PROPERTY_GET_SET(type, property, setter) CATEGORY_PROPERTY_GET(type, property) CATEGORY_PROPERTY_SET(type, property, setter)

#define CATEGORY_PROPERTY_GET_NSNUMBER_PRIMITIVE(type, property, valueSelector) \
    - (type) property { return [objc_getAssociatedObject(self, @selector(property)) valueSelector]; }
#define CATEGORY_PROPERTY_SET_NSNUMBER_PRIMITIVE(type, property, setter, numberSelector) \
    - (void) setter (type) property { objc_setAssociatedObject(self, @selector(property), [NSNumber numberSelector: property], OBJC_ASSOCIATION_RETAIN_NONATOMIC); }

#define CATEGORY_PROPERTY_GET_UINT(property) CATEGORY_PROPERTY_GET_NSNUMBER_PRIMITIVE(unsigned int, property, unsignedIntValue)
#define CATEGORY_PROPERTY_SET_UINT(property, setter) CATEGORY_PROPERTY_SET_NSNUMBER_PRIMITIVE(unsigned int, property, setter, numberWithUnsignedInt)
#define CATEGORY_PROPERTY_GET_SET_UINT(property, setter) CATEGORY_PROPERTY_GET_UINT(property) CATEGORY_PROPERTY_SET_UINT(property, setter)

#define CATEGORY_PROPERTY_GET_BOOL(property) CATEGORY_PROPERTY_GET_NSNUMBER_PRIMITIVE(BOOL, property, boolValue)
#define CATEGORY_PROPERTY_SET_BOOL(property, setter) CATEGORY_PROPERTY_SET_NSNUMBER_PRIMITIVE(BOOL, property, setter, numberWithBool)
#define CATEGORY_PROPERTY_GET_SET_BOOL(property, setter) CATEGORY_PROPERTY_GET_BOOL(property) CATEGORY_PROPERTY_SET_BOOL(property, setter)


#define CATEGORY_PROPERTY_GET_NSVALUE_PRIMITIVE(type, property, valueSelector) \
    - (type) property { return [objc_getAssociatedObject(self, @selector(property)) valueSelector]; }
#define CATEGORY_PROPERTY_SET_NSVALUE_PRIMITIVE(type, property, setter, valueSelector) \
    - (void) setter (type) property { objc_setAssociatedObject(self, @selector(property), [NSValue valueSelector: property], OBJC_ASSOCIATION_RETAIN_NONATOMIC); }

#define CATEGORY_PROPERTY_GET_SEL(property) CATEGORY_PROPERTY_GET_NSNUMBER_PRIMITIVE(SEL, property, pointerValue)
#define CATEGORY_PROPERTY_SET_SEL(property, setter) CATEGORY_PROPERTY_SET_NSNUMBER_PRIMITIVE(SEL, property, setter, valueWithPointer)
#define CATEGORY_PROPERTY_GET_SET_SEL(property, setter) CATEGORY_PROPERTY_GET_SEL(property) CATEGORY_PROPERTY_SET_SEL(property, setter)

#import "Something.h"

@interface Something (Properties)

@end

Something+Properties.m

#import "Something+Properties.h"
#import <objc/runtime.h>

@interface Something ()
@property (nonatomic) BOOL thing;
@end

@implementation Something (Properties)
CATEGORY_PROPERTY_GET_SET_BOOL(thing, setThing:);
@end