Our template emission strategy is broken

[Walter Bright via Digitalmars-d]

On 11/11/2015 4:16 PM, Iain Buclaw via Digitalmars-d wrote:
> The main problem for seamless support is having some way to generate the C++
> typeinfo in D to allow work across boundaries.

I suspect that is unnecessary.

The whole point of D's C++ interface is to interface with C++ code. Defining C++ 
classes in D code that does not link to any C++ code that also defines those 
classes won't be supported. I.e. we can reply on the C++ code generating the 
necessary C++ typeinfo. The generated D code only has to link to it, i.e. 
generate an extern reference to the name of the typeinfo.

Similarly, we never need to throw a C++ exception from D code. All we need to do 
is call a library function written in C++ that throws it for us.

What D does need to do is support catching an std::exception*, or a class 
derived from std::exception. I believe we are on solid ground in not supporting 
any other C++ types being thrown.

Nor do I believe we need to catch C++ objects with catch(...). Catching C++ 
objects will need an explicit catch(std.exception*).

Over time, perhaps it may become apparent that we do need to support more kinds 
of C++ types being thrown. But it is not necessary to get this lead brick 
airborne, and we shouldn't waste time worrying about it.