C++17 feature proposal: Allow std::data, std::size, std::empty

[Daniel Cheng]

We already have our own backported versions of std::data and std::size; let's remove them and replace them with the standard version. We don't have a std::empty, but allowing it alongside the other two makes sense to me.

Daniel

[Jeremy Roman]

We do have base::empty. More generally I think anything from cxx17_backports.h should likely move to the genuine article. :)

On Thu, Jan 6, 2022 at 4:12 PM Daniel Cheng <dch...@chromium.org> wrote:

We already have our own backported versions of std::data and std::size; let's remove them and replace them with the standard version. We don't have a std::empty, but allowing it alongside the other two makes sense to me.

Daniel

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[Avi Drissman]

Strong concerns for the general statement about cxx17_backports. The items in that file should be addressed one at a time to ensure we don't backslide on undefined behavior (looking at base::clamp specifically).

+1 for migrating our versions to std for the specific functions std::data, std::size, std::empty.

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[Lei Zhang]

+1 to what avi@ said.

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[Peter Kasting]

+1

PK

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[Daniel Cheng]

Agreed: I saw the CHECK() in base::clamp() and that's why I specifically didn't broaden this proposal to include all of them. And if we exclude base::clamp(), then lumping in other random functions into this proposal seemed a bit too random.

Daniel

[Peter Kasting]

It looks like we had agreement to do the narrow change here, but this didn't land?

PK

On Thu, Jan 6, 2022 at 1:12 PM Daniel Cheng <dch...@chromium.org> wrote:

We already have our own backported versions of std::data and std::size; let's remove them and replace them with the standard version. We don't have a std::empty, but allowing it alongside the other two makes sense to me.

Daniel

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[Daniel Cheng]

Let me create a bug here. I think I was planning on doing this in one atomic CL, but given the variants, it's probably better to stage this one out into multiple CLs. I'll send a CL to update the wording though.

Daniel

[Daniel Cheng]

This should be done now. I need to clean up a few header files, but it looks like the last change to delete base::{data,empty,size} isn't going to get reverted. Thanks to thestig@ for all the reviews!

Daniel

[Lei Zhang]

\o/

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