In the new Swift language from Apple, how does one call Objective-C code?
Apple mentioned that they could co-exist in one application, but does this mean that one could technically re-use old classes made in Objective-C whilst building new classes in Swift?
Objective-C is a platform-independent language, whereas Swift is platform-dependent. Writing non-platform-dependent code (business logic libraries) in Swift would thus not be wise. However, writing platform-dependent code in it (interface related for example) would be perfectly fine. Not to say it would be a good idea, however it is definitely an interest.