Save yourself the trouble and just fork and maintain https://github.com/tcbrindle/span . It's already released under BSL-1.0, so no problems there either. Then there's another one, https://github.com/martinmoene/span-lite, equally BSL-1.0. It appears std::mdspan is slightly more of a challenge.

+1. They're Boost licensed, and Boost friendly authors to boot. I personally use span-lite. It works well on C++ 98, incidentally. In any case, implementation is easy, it'll be the documentation which is hard, as always. Niall

On 17/06/2019 15:40, Hans Dembinski wrote:

Dear degski and Niall,

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On 17. Jun 2019, at 14:24, Niall Douglas via Boost wrote:

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Save yourself the trouble and just fork and maintain https://github.com/tcbrindle/span . It's already released under BSL-1.0, so no problems there either. Then there's another one, https://github.com/martinmoene/span-lite, equally BSL-1.0. It appears std::mdspan is slightly more of a challenge.

+1. They're Boost licensed, and Boost friendly authors to boot.

thank you for the pointers. I will check their implementations. Do you know why were these not proposed/accepted for inclusion in Boost?

Almost certainly because they lack the time, patience, and fortitude of will. But you'd have to ask them.

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I personally use span-lite. It works well on C++ 98, incidentally.

In C++ 98 and without decltype and declval, it is more difficult to restrict the overloads of the templated constructors of span, I have to see how they do that.

I've fired it into C++ 98 codebases and it "just worked". I don't doubt there will be some corner case gotchas.

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In any case, implementation is easy, it'll be the documentation which is hard, as always.

For a clone of std::span, one can base the documentation on cppreference.com, which is better than developing from scratch.

I suspect the tutorial will be the most painful part. Like, when and why to use string_view vs span vs iterator pairs vs range vs pointers? Niall