[libcxx-commits] [PATCH] D115999: [libc++][format] Finish P0645 Text Formatting.

Mon Jan 24 08:48:32 PST 2022

Mordante added inline comments.

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Comment at: libcxx/docs/ReleaseNotes.rst:43-45
+  functions are known to be inefficient; both in memory usage and performance.
+  The implementation isn't API or ABI stable and therefore considered
+  experimental. (Some not yet implemented papers require an API break.)
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ldionne wrote:
> Quuxplusone wrote:
> > Do we need to mention `LIBCXX_ENABLE_INCOMPLETE_FEATURES` here? I don't really know how it works.
> My understanding is that since the original `format` paper will effectively fully implemented, we would not use `LIBCXX_ENABLE_INCOMPLETE_FEATURES` here. Was that your intent @Mordante?
I intend to keep it. We added that in LLVM 13 since `std::format` wasn't ABI stable, which it's still not. There are some ABI breaking LWG issues and papers retroactively accepted in C++20. At the moment there's even one ABI breaking LWG issue active https://cplusplus.github.io/LWG/issue3576. Having it not ABI stable also makes it easier to look at possible optimizations in the implementation. I expect to be able to finish all remaining work in the LLVM 15 timeframe.

We could montion the macro, it's not really a new feature, but might be a nice reminder. (We use the same feature flag for our ranges implementation.)

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D115999/new/

https://reviews.llvm.org/D115999