Thanks for all the answers!
Is it possible to register, say, a base class, and have all the
subclasses then registered automatically?
My idea would be to make it as transparent as possible for the plugin
implementation, and also not having to depend on it.
A.
There is a library that creates reflection metadata for you. [1]
It seems a bit outdated and has some not-that-obvious compilation
errors(for example getting ctor and callling it with runtime known type,
or some other non template stuff), but other than that seems to be
working (note that I didn't thorougly tested it, but its unittests
succeeds on DMD 2.080 for both Windows x86 mscoff & x64 )
[1] https://code.dlang.org/packages/witchcraft