Add skills for {fmt}

[mingxwa]

Changes

• New header file proxy_fmt.h with 2 new skills: pro::skills::fmt_format and pro::skills::fmt_wformat.
• Added unit test cases accordingly.

Note that proxy_fmt.h is not self-contained. Users need to include both proxy.h and the {fmt} library (version 6.1.0 or later) before proxy_fmt.h. Spec will be updated separately.

Resolves #279

[zhiyongww]

This is awesome. I'm wondering if we could remove the dependency on std::format (i.e., #include ) if we use {fmt}.

[mingxwa]

Hi @zhiyongww, removing dependency on std::format is not currently on our roadmap. While pro::skills::format and pro::skills::fmt_format are defined separately in the upcoming 4.0 release, you can simply ignore pro::skills::format if you don't use it. Otherwise, if you find removing #include <format> from proxy.h useful in your scenario, could you share more context? Thank you!

[zhiyongww]

Hi @zhiyongww, removing dependency on std::format is not currently on our roadmap. While pro::skills::format and pro::skills::fmt_format are defined separately in the upcoming 4.0 release, you can simply ignore pro::skills::format if you don't use it. Otherwise, if you find removing #include <format> from proxy.h useful in your scenario, could you share more context? Thank you!

Hey @mingxwa, thanks for the reply. In our company, std::format is not available in our production environment even though we use C++20. I was thinking about using the proxy library to replace virtual functions to improve the performance of our program. Thanks.

[tian-lt]

Also update the "single header"s in FAQ?