Superscript and Subscript Characters in General Use

[Alastair Houghton]

On 4 Jan 2017, at 14:20, Marcel Schneider <charupdate at orange.fr> wrote:
> As a result of prior discussions, we know that other list participants do use e.g. 
> superscript characters in a more extensive way. 
> 
> I think there are two levels of action: 
> 
> (1) to encode new preformatted characters;
> (2) to encourage re-use of already existing ones. 
> 
> I understand that Unicode is consistently reluctant in both, while ISO/IEC is able 
> to do more in (1) given that they sometimes add (or remove) characters to(/from) 
> the new repertoire, and National Bodies are in a position to do (2) through usage 
> recommendations of their own. Let alone all the other people who may use or not 
> use available preformatted characters for any purpose, eventually sharing the hint 
> and—in the best case—the means to input them efficiently. 
> 
> Or am I missing something?
> 
> Given that the WG of the French standard keyboard is actually interested in getting 
> encoded a new ordinal indicator (kind of 'ᵉ'), I feel the more urged to stay tuned, 
> and to comment on subsequent e-mails, too.

I can understand the desire to encode the new ordinal indicator.

Perhaps another option worth contemplating might be to standardise some control code points, to provide a mechanism for “plain text” to include the necessary minimum of formatting information without additional markup.  The advantage of this approach is that it would make it explicitly obvious that Unicode wasn’t going to include further super or subscript forms, while providing everyone that wants them with access to a full set of super or subscripts subject to system (or font) support.

A simple form of this might be to encode the new zero-width modifier code points SUBSCRIPT and SUPERSCRIPT that work somewhat like the variation selectors, so e.g.

  U+0032  DIGIT TWO
  U+????  SUPERSCRIPT
  U+0033  DIGIT THREE
  U+????  SUBSCRIPT

would display as ²₃ on fonts that supported the new modifiers.  The advantage of taking this very simplistic approach is that it can be dealt with in the OpenType (or AAT) tables in modern fonts, rather than necessitating changes to rendering code.  It is also obviously not an attempt to replace markup, but will cope with most common “plain text” uses.

Kind regards,

Alastair.

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