[Feature Request]: direct support for C++ interoperability

[mppf]

Currently, Chapel has pretty good C interoperability (through extern blocks, c2chapel, extern and export procs/vars). It comes up semi-regularly that one needs to work with a C++ library. However, there are quite a few things that might be needed for C++ interoperability.

Some specific points to get ideas going:

• Calling a function that happens to be C++ but doesn't rely on C++ features?
• Calling overloaded C++ functions?
• C++ methods callable as Chapel method calls?
• Is calling virtual methods important?
• What about RAII behavior of C++ objects types used from Chapel?
• Instantiating C++ templates with Chapel types / through interop?

This issue is a place to collect information about what features would be needed in practical cases. If you run into a practical case where better C++ interop would have helped, leave a comment here summarizing the features you would use.