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The Objective-C protocol naming trifecta

Objective-C protocol names throughout history seem to fall into three distinct conventions:

  • some are named after what a conforming object provides. Thus we have DBProperties, DBEntities, DBTypes and the like in Database Kit.
  • others are named after what the object is doing. Thus we have NSCoding, NSLocking, IXCursorPositioning etc.
  • still others are named after what the conforming object is. NSTableViewDataSource, NSDraggingInfo etc.

I think I prefer the second one. It emphasises the dynamic message-sending nature of the language: “because you’re sending messages from this protocol, I’ll act like this”.