On 24/10/2024 07.46, Mateusz Pusz wrote:
>> Could you give an indication of the respective use-case?
>
> Here is an example for subscript and multiplication sign:
>
> static_assert(unit_symbol(mag_ratio<1, 18000> * metre / second) == "[1/18 × 10⁻³ m]/s");
> static_assert(unit_symbol<usf{.encoding = portable}>(mag_ratio<1, 18000> * metre / second) == "[1/18 x 10^-3 m]/s");

Thanks.

>> Could you give a sample std::format invocation where this would happen?
>> In particular, I'm opposed to throwing an exception if the value of a
>> format argument (not the format string) happens to be a little off.
>
> Formatting of a dot (⋅) can be found at https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2024/p3045r3.html#unit-formatting <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2024/p3045r3.html#unit-formatting>.
> The exception is thrown because of a problem in a format string. Someone requested portable output and a dot as a separator.

Format strings are parsed at compile time, I thought, so this
could be a compile-time error?

>> inline constexpr auto π /* U+03C0 GREEK SMALL LETTER PI */ = pi;
>
> Thanks. I think the second option is a better option, as a user can directly copy-paste glyphs into the code. Do we agree that it is how it should appear in the wording?

I don't know whom you address with "we". First, a little chat on the
reflector is not a good venue to establish meaningful consensus for the
WG21 process. Second, SG16 is not the appropriate forum to decide on
wording. LWG does that. If LWG doesn't agree with the wording, they
can ask for a change, but at the very least all information *they*
need to know about the funny character is present with the style above.

Jens