Mutating MFC to Cocoa

I am making progress converting the view hierarchy of the timeline to cocoa. In the about face I am working through the classes and interfaces that are defined in MFC and attempting a mechanical conversion where possible. In my first cut I do the following:

• Mutate the all 'interface' definitions to protocols.
• Mutate all pure virtual base classes into protocols.
• Mutate all other classes as objective C classes.
• Where a class is based on multiple inheritance of a C++ class (typically mix-in classes) this is expressed as a protocol and I write a subclass of the mix-in class that funnels calls to an object of that protocol.
• Comment out what is obviously not needed for a first cut.

I do the conversion bit by bit getting the compiler to guide me. It is a relentless, tireless guide. At best I get logic and code that is very close to what I need at worst I get a fill-in-the-dots template. Importantly the code dovetails in nicely into the existing code.