Cocoa/Objective-C - Can i somehow see the implementation files?

Question

I believe i can learn thing or two if i can see the implementation files (.m files). Is there any way the i can view NSString.m or NSNumber.m files? and others? If i try to find these files using spotlight, i get nothing.

Answer 1

No, most (all?) of the Cocoa library implementations are only distributed in a compiled binary form. You could disassemble them, but that's probably against the Mac OS X EULA, and it also wouldn't help you understand them at all.

You could take a look at Cocotron, which is an open-source implementation of Cocoa. It won't be exactly the same, but at least for the core classes, it will be virtually identical.

Answer 2

Many of the basic cocoa classes, like NSString and NSNumber, are implemented in core foundation and "toll-free bridged" to objective-c classes. Core foundation is a C (not ObjC) API and the source is available as part of the Darwin open-source project.

So, to see how NSString or NSNumber is implemented under the hood, follow the link above and take a look at CFString and CFNumber, respectively (you'll need an Apple developer account, but registration is free).