Another aguement to adding at to std::span is that we should add at() to
C-Style arrays and pointers. This would be false for pointers if we were
using pointers to manage a linked list. This might also confuse C
programmers when they are using C++ because we have added at to C
constructs just for consistency is span

On Mon, Apr 20, 2020, 4:39 AM Ville Voutilainen via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> On Mon, 20 Apr 2020 at 12:33, Lyberta via Std-Proposals
> <std-proposals_at_[hidden]> wrote:
> >
> > Ville Voutilainen:> 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==.
> > Unsafe code must be inconvenient to write.
>
> ..so as to make perfectly safe code inconvenient to write, too.
>
> > For that reason reinterpret_cast is named that way. The fact that
> > std::set<std::string_view> and std::map<std::string_view, T> compile is
> a bug.
>
> In java, that's perhaps a correct statement.
>
> > > Also, by that definition,
> > > references and pointers are similarly unsafe
> > Sure, have you ever seen std::set<char*> or std::map<char*, T>? At least
> it is common knowledge that raw pointers are unsafe and
> > shouldn't be used in most code.
>
> Right. Ban those uses. Programmers, after all, need hand-holding from
> people who have no idea what they're talking
> about.
>
> > > 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.
> > Sure, if you want deep comparison, use explicit code. For pointers you'd
> do *i == *j. Dereference is explicit.
>
> The data can change at any time. Do not allow such comparisons. In
> fact, do not allow the comparisons of anything,
> the data can change if non-const references to it have ever escaped
> anywhere.
>
> This sort of thinking is a disease.
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