Where can i find a document explaining how Objective-C is implemented

Question

I mean the fundamental runtime. How is method dispatching implemented (via a selector hashtable?). What is a selector anyway? How is the object model as you can add methods later with some low level API etc.

I need to look at it from a compiler programming point of view, not a simple user of the language.

Answer 1

Use the source.

http://www.opensource.apple.com/source/objc4/objc4-437/

And for parsing, look to Clang:

http://clang.llvm.org/get_started.html