KVC Helper Macros

gistfile1.m

// KVC Compile-time Helpers
//
// These macros allow simple compile-time checking of KVC keypaths, as long as the getter methods for properties
// match up with their property names (i.e. if the property 'available' has the getter method 'isAvailable', these
// macros will break)

#define Key(class, key)			(0 ? ((class *)nil).key, (NSString *)nil : @#key)
#define InstanceKey(instance, key)	(0 ? ((__typeof(instance))nil).key, (NSString *)nil : @#key)
#define SelfKey(key)			(0 ? ((__typeof(self))nil).key, (NSString *)nil : @#key)
#define ProtocolKey(protocol, key)	(0 ? ((id <protocol>)nil).key, (NSString *)nil : @#key)


// Example usage, where the class Person has a property or method 'name'

NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:Key(Person, name) ascending:YES];