Hi SG16 :-)

At the last meeting about units, I said that we do not have to decide on any specific Unicode symbols for now, as the systems of units are the subject of the next papers. It turns out I was wrong :-(

We need a few Unicode characters for the first proposal. Those are:

NameSymbolC++ codePortable alternative
Superscript Zero⁰u8"\u2070""0"
Superscript One¹u8"\u00b9""1"
Superscript Two²u8"\u00b2""2"
Superscript Three³u8"\u00b3""3"
Superscript Four⁴u8"\u2074""4"
Superscript Five⁵u8"\u2075""5"
Superscript Six⁶u8"\u2076""6"
Superscript Seven⁷u8"\u2077""7"
Superscript Eight⁸u8"\u2078""8"
Superscript Nine⁹u8"\u2079""9"
Superscript Minus⁻u8"\u207b""-"
Multiplication Sign×u8"\u00d7""x"
Mathematical Italic Small Pi𝜋u8"\U0001D70B""pi"
Per Mille Sign‰u8"\u2030""%o"
Dot Operator⋅u8"\u22C5"<none>*

* This option is valid only for UTF-8 encoding. Otherwise, we propose to throw an exception during format string processing.

1. Did I choose the correct Unicode symbols for those?
2. Is the C++ spelling correct? Should we spell them in the spec with '\u', '\U', or maybe some other way?
3. Are the portable alternatives fine (especially "%o" might be controversial above)?
4. Is there a better way to spell `inline constexpr auto 𝜋 = pi;` to be explicit about the specific Unicode symbol used for the identifier?

Best

Mat