Charles: Yes to using generic programming in TextMate.

The core of the application is an STL conforming container which expose only a handful of member functions, and the storage is accessed through iterators. This means that I can use all the standard library functions on my text storage, which I do a lot. It also means that everything I build on-top of it, is ignorant about the actual storage, which means they function on whatever unit they are given as input (via iterators), be it current word, line, selection, column selection, or entire document.

This might just sound like abstraction, but the beauty is that this abstraction has zero overhead when it comes to both performance and more importantly (IMHO) syntax.

For example advancing the caret to the next space is just a matter of:

caret = std::find(caret, document.end(), ' ');

What’s important to notice here is that std::find is not a function I wrote. It is a standard re-usable algorithm from the standard library, unlike e.g. Foundation Kit, where each container has its own indexOfObject: and related methods.

Being able to use standard functions like that not only cuts down on the amount of code I have to write, but it is a clear testament to the interchangeability of things with STL, which is a tremendous win when trying to keep the complexity and inter-dependency of components to a minimum.

As for bringing these concepts to Objective-C, I don’t really see it working. There would of course be a performance penalty, but the syntactical overhead would also be big. The fact that Objective-C is very dynamic is partly responsible for this, because the C++ compiler does a lot of work compile-time to make the proper choices, e.g. select the proper function/operator to call based on argument types or which namespace arguments are from, perform implicit type conversions when necessary, handle proper construction and destruction of all stack-allocated resources, including potential member data for such (and even does proper deconstruction when exceptions are thrown during partial construction), etc.

STL makes use of close to every single C++ feature, and C++98 had a lot of stuff added solely to better support STL concepts. So without the C++ compiler, one would first have to re-implement what it does, and I don’t think that is feasible with Objective-C.

As I see it, Objective-C and C++ solve problems in two different domains, and so does it rather differently.

Anyway, I was wondering if you were using any of these concepts in TextMate's implementation, and/or if you see any possible implementation of these concepts into ObjC (its dynamic nature might be a plus, but it is likely that it would also make an implementation slower).