On Thursday, 22 June 2017 at 14:30:31 UTC, jmh530 wrote:
I was looking through the C++ standard library headers and noticed <typeinfo> that has a typeid also. One difference with D is that it is opt-in as there is some cost using it.
C++ also leaves most the properties for typeinfo to be implementation defined, meaning things like .name can just return an empty string. I believe the only thing the standard requires is consistent opEquals.
Additionally, C++ will only generate it for classes with at least one virtual member (the main use of it is dynamic casts, or substitutes thereof, and using those is often bad object oriented design anyway!)
I suppose I'm wondering what other differences there are. Could TypeInfo be made optional in D, like it is in C++?
Much of it can, yes, and it can also be defined to offer less (or more! I'm actually a fan of runtime reflection) than it does now. There's an effort to convert typeinfo to be library templates instead of a compiler-provided blob like it is now.
But, even in C++, RTTI is necessary for dynamic casting... so how is D going to address that? I think it is necessary, but can prolly be quite minimal. I will think about it more later.
