> I can't think of a compare method in the Objective-C core lib (the biggest nil-swallowing lib I know of). Does anyone know of one? Would be interesting to see how it's handled and if it causes issues.
Maybe I misunderstood you, but there is plenty of compare:'s in Cocoa: http://cl.ly/image/1a112f1B1W1g.
They all return an enum that's either -1, 0 or 1.
I can't think of a compare method in the Objective-C core lib (the biggest nil-swallowing lib I know of). Does anyone know of one? Would be interesting to see how it's handled and if it causes issues.
You could return an enum, which would allow you to use non-obvious values (Lower = 1, Equal = 2, Higher = 3), though this would make it a bit of a pain to interface with C-style libs.
Obviously the presence of a work-around doesn't mean nil-swallowing is a good idea, but rather cements the idea that library authors need to put in extra effort to make sure nil receivers are handled appropriately.