I'd like to see concrete discussion of the fact(?) that all view-adaptors currently inherit from view_interface. Is that an accident of vendor-implementation? or an accident of specification? or is it really deliberate and we can rely on it not to change in the future?

This should definitely be worth discussing.
It seems LWG 3549 needs to be mentioned (even though I didn't initially intend to do so), after which I think inheriting `view_interface` may be an option over inheriting `view_base` *in any way*, even though the former may not currently be able to synthesize any functions through the base class (also see my naive SO question back in the day: Why does `basic_istream_view` inherit `view_interface?`, and ironically, my LWG 3715  proved the answer. :) )

In the proposed wording, `ranges::distance` should be `ranges::size`. (They do the same physical thing in this case, but the latter better reflects your intent.)

I personally prefer `ranges::distance`, which avoids the implicit conversion (i.e. difference type) before comparing with an index value, but `ranges::size` definitely sounds reasonable, and perhaps this should be decided by the LWG. I'll add a discussion for this.

Thanks again for the valuable feedback! 

Hewill

Arthur O'Dwyer <arthur.j.odwyer@gmail.com> 於 2023年11月16日 週四 上午10:41寫道：
On Wed, Nov 15, 2023 at 8:42 PM Hewill Kang via Std-Proposals <std-proposals@lists.isocpp.org> wrote:

I suggest that the first word of the proposal shouldn't be "Finally". :)

I'd like to see concrete discussion of the fact(?) that all view-adaptors currently inherit from view_interface. Is that an accident of vendor-implementation? or an accident of specification? or is it really deliberate and we can rely on it not to change in the future?
I.e., I'd like you to list out a bunch of view-adaptors and view-factories (at least these four: take_while_view, iota_view, subrange, common_view) and show how deliberate is the wording that makes them inherit from view_interface. Or if there's already some kind of blanket wording that says "All standard view adaptors inherit from view_interface...", that's even better, and should be mentioned.

In the proposed wording, `ranges::distance` should be `ranges::size`. (They do the same physical thing in this case, but the latter better reflects your intent.)

Other than that, seems reasonable to me.

Cheers,
Arthur