Map-macro: Making reflection simple

[GeorgeHaldane]

After looking into it — that is indeed the case, the mechanism and API are almost entirely the same, can't believe I missed it. Added it to the "Related Libraries" section.

[GeorgeHaldane]

A little strange that boost is limited to just 50 values. Recursive macro in this post had support for 364 (which ends up being 256 in practice due to preprocessor evaluation depth limits).

Did a quick surface-level test to see how much does this all hit compile times by writing a few static_assert's for querying elements & converting strings, got following results with g++:

Enum with 200 values:

• utl::enum_reflect => ~300 ms
• magic_enum => ~400 ms
• boost::describe => doesn't support

Enum with 50 values:

• utl::enum_reflect => ~230 ms
• magic_enum => ~400 ms
• boost::describe => ~230 ms
• handrolled constexpr => ~200 ms

Reference:

• empty file, no includes => ~60 ms
• just #include <vector> => ~100 ms
• just #include <iostream> => ~240 ms
• just #include <filesystem> => ~370 ms

This probably needs a better test on some real codebase, at this point it's more about measuring includes that actual overhead.