Magic Enum C++ VS pfr

I'm not sure this is quite what you're asking for, but this library has been super helpful to me in the past : https://github.com/Neargye/magic_enum

Also, a shoutout to Magic Enum: https://github.com/Neargye/magic_enum

What does this have to offer over magic_enum?

But it's a hack, and I prefer not to use hacks in production, because of their significant limitations:

Why reinvent the wheel? magic_enum

I strongly recommend that you instead use magic_enum::enum_cast

Magic Enum provides that.

While I can understand the sentiment behind that it makes for a poor solution because people seeing the enum will assume it's a valid entry. A better solution is to use something like magic enum for that case.

magic_enum by far. It has an extreme amount of black magic, and compiler specific stuff all abstracted away behind its extremely neat user interface.

magic_enum

The code is relatively short and can be groked with a few coffees: https://github.com/boostorg/pfr/tree/develop/include/boost/pfr ; if you're using C++17 it uses a binary search (https://github.com/boostorg/pfr/blob/develop/include/boost/pfr/detail/fields_count.hpp) to count the number of fields in a struct, by starting by the observation that a likely majorant on the number of fields in a struct is sizeof(the struct) * CHAR_BIT, assuming not too many [[no_unique_address]] tomfooleries. Then once this count is known it's possible to simply map them as a tuple through sheer brute force and destructuring: https://github.com/boostorg/pfr/blob/develop/include/boost/pfr/detail/core17_generated.hpp

I wonder if the c++ approach of boost.pfr would be portable to rust ? It allows reflection on aggregates without needing to annotate anything: https://github.com/boostorg/pfr

It is an 'interesting' meta-programming problem though (wasted many weeks on it myself, fixed a small gcc bug - a 'uniform init' edge case and filed an issue with magic_get Reflecting array members of aggregate structs).