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Re: std::span

From: Ville Voutilainen <ville.voutilainen_at_[hidden]>
Date: Mon, 20 Apr 2020 12:13:17 +0300
On Mon, 20 Apr 2020 at 11:01, Lyberta via Std-Proposals
<std-proposals_at_[hidden]> wrote:
> Barry Revzin via Std-Proposals:
> > It's actually somewhat worse than this. span used to have comparison
> > operators, and then people fought to remove them.
> Because it should be shallow comparison or no comparison at all. span is like a "fat" pointer, it doesn't own the data and data
> can change at any time. Having deep comparisons would make a lot of very unsafe code compile.
> I would say that std::basic_string_view should also have its comparison operators removed for the same reason.

That "unsafe code" will compile anyway, you've just made it
inconvenient to write - we need to use a compare() function
as opposed to just using operator==. Also, by that definition,
references and pointers are similarly unsafe, and comparison
through them are surely banned in this wonderful Regular World that is
next to unusable.

A major use case for span and string_view is parsing - get a sub-range
to something, compare it like it's a whole
range. But noooooo, in a Regular Dogma that use case is not accepted.

Received on 2020-04-20 04:16:25