[NTG-context] accessing glyphs in the private area

Ulrike Fischer news3 at nililand.de
Tue Oct 2 13:39:23 CEST 2018

Am Tue, 2 Oct 2018 11:29:46 +0200 schrieb Hans Hagen:
>>  Can't you check for a free range instead?
> sure, but then i also loose some functionality in context (unless i gho 
> for ugly solutions) ... as all glyphs are supposed to have a name access 
> by name is a pretty good alternative

Well in my view name and code point are both valid and useful
accesses (and I wouldn't trust names too much). 

Beside this:
xetex has (for non-legacy fonts) primitives for all accesses: by
char (unicode), slot and name. 

luatex hasn't, here the only (primitive) access are commands like
\char which expect a number; the name field of a character is marked
as "unused" in the manual. 

Neither has the generic fontloader imho some suitable primitive
command for name access. All the examples in the generic folder uses
numbers or direct input: e.g. \Uchar"1D49D or \Uradical "0 "221A

So it is imho quite natural that people who write code and packages
expect the access by \char + code point to work. Why should I bother
with a (perhaps font specific) glyph name if I can simply look up a
clear code point number in a table?  

And if I got it right you are reserving a specific space to have
stable numbers internally, so you are caring about numbers too ;-)  

> the main issue is that there are fonts that use private > 0xFFFF space 

I don't know. Wikipedia says that code2000 uses plane 15 but I
didn't check. 

Ulrike Fischer 

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