[vtk-developers] Added __WRAP__ preprocessor macro to replace BTX

[David Doria]

> #if !defined(__WRAP__)
> // code exclusion section
> #endif

This is great. The ETX/BTX was always unintuitive to me (I actually
still don't know what they stand for). Actually using the word "wrap"
makes much more sense.

> when a VTK header file breaks the wrappers, it should be considered a
> bug in the wrappers, not something to be fixed in the header.

That's a great philosophy.

Keep up the good work.

David