Welcome!
1. What is the current support for calling C/C++ free functions from D? What level of mangling is supported? What data types can be passed without translation from D to C/C++?
3. How can a C++ object be used from D? Can C++ methods be called from D? The question applies to value types - no virtuals - and polymorphic types with virtuals, inheritance etc. And of course simple C structs.
5. How about the other way? Can a C/C++ function call a D function?
http://dlang.org/cpp_interface.html
2. How about template functions? Is it possible to call a C++ template function from D?
4. How about template objects? One issue is that many C++ interfaces pass std::string and std::map<..., ...> as parameters. How feasible is to manipulate such objects in D?
Not yet. http://forum.dlang.org/thread/lslofn$2iro$1...@digitalmars.com
