I'm with brainsalad and geneg1, abstract the interfaces and use clang and the new Roslyn compilers from MSFT as your parsing/tagging engine, and fall back to your own tagging engine when they don't support the language. I hope you can go there some time in the not-too-distant future.
Oh yes, hooking into the Microsoft compilers for tagging information as Visual Studio does would be awesome for coding on Windows.
Right now, the IDEs have better tagging support than SlickEdit
SlickEdit is better in so many other ways, but I barely use it for Objective-C coding since XCode's completion and error detection is just lightyears better. If the demand for iOS work keeps up, I'm going to have a hard time justifying renewing my SlickEdit all platform license.
I've given some thought to using slick-C to interpret Clang parse trees in order to produce SlickEdit tagging info, but I just have too much on my plate already.
I hope the SlickEdit team reads these posts. Come on SlickEdit! We want next gen tagging! Ctags style tagging is SO last century!!