Unit symbols using unicode characters?

[burnpanck]

Hey, is there already any committee/expert feedback on unicode names for unit symbols? It appears that both Ω and µF are acceptable as identifiers for both GCC and clang (godbolt). It appears to me that those identifiers should be accepted by any standard-conforming compiler (assuming that the specific unicode symbols here have indeed the XID_Start property), though I'm no expert.
It's likely that not everybody would prefer those variants over pure-ascii names, so we could consider supplying both variants. To support users using compilers which do not support such unicode identifiers, there could be demand for a preprocessor switch to disable the unicode variants completely.

[mpusz]

is there already any committee/expert feedback on unicode names for unit symbols? It appears that both Ω and µF are acceptable as identifiers for both GCC and clang (godbolt).

I am not sure what is your concern here? Unicode symbols are supported by this library and all the major compilers. They are also the default for all the units that require them. ISO C++ Committee wants Unicode characters as default as well. The only thing that might change here is the actual encoding of a specific character, as the same glyph may often be obtained with a few different Unicode sequences. SG16 promised to help with that when we provide papers with systems of units.

Non-unicode alternatives have one big issue. They are not specified in SI or ISO 80000. This means that for many symbols, we do not know what is the best alternative. For example, how to replace Ω with non-Unicode text? Even if we chose something we might not be content with similar but different choices done by other vendors.

[mpusz]

Ah, now I understand what you meant. You would like to use Unicode characters for the identifiers in the si::unit_symbols namespace, right? I am not sure if that is portable. I will check with the SG16 on the nearest occasion.

[burnpanck]

Exactly. Sorry for not being clear. According to cppreference.com on identifiers, some unicode characters are allowed in identifiers. I was not able parse the unicode specification of that XID_Start property linked from cppreference, so I just checked godbolt for Ω and µ instead.

[mpusz]

The biggest problem I see with that is that the user would probably need to copy-paste those symbols into the source code, as we can't type them with regular keyboards.