Objective-C macros

autoscoped.h

// GCC Attribute for autoscoped Obj-C objects
// Source: http://www.cocoabuilder.com/archive/message/cocoa/2009/3/13/232287

#define autoscoped __attribute__((cleanup(releaseObject)))

static inline void releaseObject(id *object)
{
    [*object release];
}

- (void) demo
{
    autoscoped NSArray *anArray = [[NSArray alloc] init];
    // do something with anArray
}

isEmpty.h

// A quick check if an object is empty
// Source: http://www.wilshipley.com/blog/2005/10/pimp-my-code-interlude-free-code.html

static inline BOOL isEmpty(id thing) {
	return (thing == nil)
		|| ([thing respondsToSelector:@selector(length)]
			&& [(NSData *)thing length] == 0)
		|| ([thing respondsToSelector:@selector(count)]
			&& [(NSArray *)thing count] == 0);
}

object_creation.h

// Helpful macros for object creation
// Source: http://cbarrett.tumblr.com/post/53371495/some-helpful-macros-for-object-creation

#define NSARRAY(...) [NSArray arrayWithObjects: __VA_ARGS__, nil]
#define NSDICT(...) [NSDictionary dictionaryWithObjectsAndKeys: __VA_ARGS__, nil]
#define NSSET(...) [NSSet setWithObjects: __VA_ARGS__, nil]
#define NSBOOL(_X_) ((_X_) ? (id)kCFBooleanTrue : (id)kCFBooleanFalse)

union_cast.h

// Use Unions (instead of type-punning) to recast Structs.
// Source: http://cocoawithlove.com/2008/04/using-pointers-to-recast-in-c-is-bad.html

#define UNION_CAST(x, destType) (((union {__typeof__(x) a; destType b;})x).b)