Using functions

After you expose the headers to Swift, it is quite simple to call functions. You can call the functions directly as if they don't have parameter names:

NSArray *addInviteeToListIfSpotAvailable
     (
     NSArray *invitees,
     NSString *newInvitee
     );
addInviteeToListIfSpotAvailable(inviteeList, "Sarah")

Xcode will even autocomplete the code for you. From your Swift files point of view, there is no way to know whether that function is implemented in Objective-C or Swift.

Using types

You can use types in the same way as functions. Once the proper header files are imported in the bridging header, you can just use the type as if it were a Swift type:

@interface Contact : NSObject
@property NSString *firstName;
@property NSString *lastName;
- (NSArray *)addToInviteeList:(NSArray *)invitees includeLastName:(BOOL)include;
@end

var contact = Contact()
contact.firstName = "First"
contact.lastName = "Last"
contact.addToInviteeList(inviteeList, includeLastName: false)

Again, from...