[XeTeX] Use of Apple Symbols font in XeLaTeX

[Jonathan Kew]

On 17 Sep 2004, at 11:29 am, Bruno Voisin wrote:

> Le 17 sept. 04, à 11:34, Bruno Voisin a écrit :
>
>> Alas this does not work. I suspect the problem is actually more 
>> serious: in XeTeX, a two-digit text character declaration such as "1C 
>> becomes a four-digit one "001C (I think);

Well, sort of... they're all just numeric constants. So "1C is really 
just another way of saying 28, and "001C is the same.

>>  but what does become a four-digit math character declaration such as 
>> "321C, where the first digit refers to the class (relation, binary 
>> operation, opening delimiter, ordinary character, etc.) and the 
>> second digit to the font family (1 for math italic, 2 for math 
>> symbol, 3 for math extension, etc.)?

This is also just a number; it equals 12828. The interpretation of the 
separate hex digits as distinct "fields" is a "magic convention" wired 
into TeX. You could define your mathchars using decimal constants if 
you like, and TeX would interpret them just the same.

>>  Is it simply "32001C?
>>
>> I am asking this because, apparently, \DeclareMathSymbol works 
>> essentially as follows, for a definition of the form 
>> \DeclareMathSymbol{\applewhitesquare}{\mathord}{applesymbols}{"25A1}
>>
>> \DeclareMathSymbol{#1}{#2}{#3}{"#4}
>> -> \set at mathsymbol{sym#3}{#1}{#2}{#4}
>> -> \mathchardef{#1}="{#2}{sym#3}{#4}
>>
>> where the arguments have been replaced by their hexadecimal numeric 
>> equivalents wherever necessary. Hence, what the \mathchardef syntax 
>> becomes in XeTeX seems crucial to the issue.
>
> Well, I should just have tried. Doing this:
>
> 	\DeclareFontFamily{U}{appsym}{}
> 	\DeclareFontShape{U}{appsym}{m}{n}{<-> "Apple\space Symbols"}{}
>
> 	\DeclareSymbolFont{applesymbols}{U}{appsym}{m}{n}
> 	% defines a new math font family \symapplesymbols
>
> 	\makeatletter
> 	\mathchardef\testwhitesquare="0\hexnumber@\symapplesymbols25A1
> 	\makeatother
> 	% \hexnumber@ is LaTeX's command for extracting an hexadecimal value 
> between 0 and F
>
> I get the error message:
>
> 	! Bad mathchar (730529).
> 	l.208 ...esquare="0\hexnumber@\symapplesymbols25A1
>
> which seems to indicate that \mathchar's larger than four digits 
> (actually larger than standard TeX's default "7FFF) are simply not 
> allowed.

Yes, so it seems.

>  There's certainly something I've figured out wrongly somewhere, 
> something's I've implicitly assumed that I shouldn't, but what?

No, I don't think there is; you're seeing an area where an 8-to-16 bit 
extension has not been attempted.

Does Omega include an extended \mathchar, by any chance? That might 
provide a model for what should be done, but at present I don't think 
you can encode character codes > 255 in a \mathchar.

The standard TeX math fonts, of course, don't use character codes > 
255, and so this wasn't a problem for supporting legacy math 
formatting; but it's a problem as we look to a properly Unicode-encoded 
future.

JK