I'm surprised to see many people doing this. But I'm wondering..
If you already got the code working in D, why not let it stay
there and write a C interface?
Company policy? Missing dynamic loading? Some build issues?
If the code could stay in D, it would seem like a good way to
slowly integrate D into a company.
As we said: D isn't mature enough.
As long as your code base isn't too complex, D is very nice but
at some point you get many stumbling blocks, bugs or missing
features which is very annoying. I like D, but it is far away
from using it instead of C++.