a character for an unknown character

[Marcel Schneider]

On Sat, 31 Dec 2016 11:01:16 +0100, Christoph Päper wrote:
> 
> Richard Wordingham :
> > 
> >> Perhaps the letters for hexadecimal digits should have been encoded
> >> separately?
> > 
> > The idea has been rejected several times.
> 
> It has indeed. That’s why two different technologies have to be used to get 
> typographically harmonic hexadecimal numbers, e.g. in CSS:
> 
> .hex {font-variant-numeric: oldstyle-nums; text-transform: lowercase;}
> .hex {font-variant-numeric: lining-nums; text-transform: uppercase;}
> 
> This works well enough for ‘01ef’ or ‘01EF’, but will fail for conventions like 
> ‘0x01ef’ and ‘01EFh’. Hence:
> 
> .hex::before {content: "0x"; text-transform: none;}
> .hex::after {content: "h"; text-transform: none;}
> .hex::after {content: "ₕ";}
> .hex::after {content: "16"; vertical-align: sub; font-size: smaller; line-height: normal;}
> .hex::after {content: "16"; font-variant-position: sub;}
> .hex::after {content: "₁₆";}

Thank you for the code. I didnʼt know this, so Iʼve tried and found that 
the automatic prefixes/suffixes cannot be copied from the web page. 
That seems to me a disadvantage.

Among the possibilities, you include Unicode subscripts. Is this current 
practice? That seems to me very interesting to follow up, as it documents 
that the stable representation scheme is already adopted. Iʼm curious to 
what extent it is so. 

The font-variant-numeric: oldstyle-nums seems not to work with any font. 
To get oldstyle numbers and lining numbers both displayed depending on 
the active option, I had to add font-family: Constantia, that has oldstyle 
digits.

I note that the "U+" prefix is missing in the list, obviously because it 
denotes more than just a hexadecimal number, and is to be hard-coded. 
This is easy when the keyboard includes an emulated numpad with hex letters 
and the "U+" as a sequence on a live key. I know that developers appreciate 
being able to type hex numbers on a numerical keypad, and consider typing 
them on the alphanumerical block, or on both (letters left-hand, digits 
right-hand) a suboptimal workaround. Further it is handy to have superscript 
and subscript digits accessed on the numpad too.

Marcel