I have written a fair amount of C++ template metaprogramming and policy based libraries. One library I wrote, in particular, was a templated generic matching e

I have written a fair amount of C++ template metaprogramming and policy based libraries. One library I wrote, in particular, was a templated generic matching engine primarily used in the self-clearing of trades. Through template policies, it could be configured to do one-to-one, on-to-many, many-to-many matching based upon template args, for example. I also did a bit of SFINAE in writing a home-grown ORM lib. I haven't really written any libs using tag dispatching, but I've certainly used my fair share (looking at you, Boost MultiIndex). You don't usually see these sorts of types wrapped for Java or .Net, and if they are, you usually have some sort of proxy in between to hide the templates.