[XeTeX] XeTeX: ready for full-time math?

[Jonathan Kew]

On 22 Aug 2006, at 12:30 pm, Will Robertson wrote:

> On 22/08/2006, at 19:13 , Jonathan Kew wrote:
>
>> That's my question
>> (above).... do people really feel a need for these? Will
>> supplementary-plane math letters become commonplace *as literal
>> characters in input text*? Comments invited!
>
> Well, I can't say I'm that keen on using them, since I prefer to  
> abstract my symbols away with meanings. But I wouldn't necessarily  
> want to assume that people don't want active plane 1 chars. Perhaps  
> an alternative would be to provide support in the same way as LaTeX  
> supports UTF8: make the initial char in the surrogate pair active  
> and scan ahead...but that's not exactly ideal, especially as XeTeX  
> input can be UTF-8 or UTF-16. (Or is it not possible at all?)

Possible, but ugly.

The input form is irrelevant, as UTF-8 input (the usual case) gets  
converted to UTF-16 for internal processing. So you could make the  
"high surrogate" UTF-16 codes \active, and let them look ahead for  
the following low surrogate, etc.... but it would be a bit of a pain  
to implement all the math alphabets that way, and if people want  
active chars scattered all over the supplementary planes (not just a  
few blocks of them) it would get really messy.

> No matter what we do, we'll get into the same mess if UTF-64 ever  
> comes along :)

Not in my lifetime, I trust! :)

JK