Re: [XeTeX] Math class initialization in Unicde-aware engine

[Joseph Wright]

On 02/12/2019 05:56, Doug McKenna wrote:

- \lccode and/or \uccode for non-letter code points
   for which an upper or lower case mapping is given

The problem with this is that earlier, it is stated that all combining mark 
code points (class code starting with 'M' in the UnicodeData.txt file) are to 
be considered letters (\catcode set to 11).  So there's an ambiguity here that 
needs clearing up.  Does the above apply to combining mark code points or not?


You've read something in that is not in the README ;)

The file says

  - `\catcode` 11 for all combining marks (Unicode class "M")

where I've very deliberately kept the TeX 'side' as what *actually 
happens* (catcode-11), not said they are 'treated as letters', or similar.


I will clarify that 'letter' here means a codepoint with Unicode 
character class "L", and is not linked to the TeX catcode.



It may be that none of the combining marks in the data file have any case 
mappings, but there's no guarantee that is true.  So the question is, if a 
combining mark has an uppercase or lowercase mapping, does that get installed 
in \lccode and/or \uccode?


Yes, or at least would be the case in principle: all code points with 
upper/lower/title properties are set up.



Also, there's a confusing typo ("can"?) in

- \lccode and \uccode for all of class "Lt" (title
   case letters) to the lower can upper case mappings
   (or if not given to the code point itself)

Should "can' be "and/or"?


It is 'and': you need to set lccode and uccode for these code points.

Joseph

Re: [XeTeX] Math class initialization in Unicde-aware engine

[Doug McKenna]

Joseph Wright wrote:

>| Er, I thought the README was reasonably clear, ah well!

Here's an example of something that's not so clear to me.

The README.md file displayed at

  

says

- \lccode and/or \uccode for non-letter code points
  for which an upper or lower case mapping is given

The problem with this is that earlier, it is stated that all combining mark 
code points (class code starting with 'M' in the UnicodeData.txt file) are to 
be considered letters (\catcode set to 11).  So there's an ambiguity here that 
needs clearing up.  Does the above apply to combining mark code points or not?

It may be that none of the combining marks in the data file have any case 
mappings, but there's no guarantee that is true.  So the question is, if a 
combining mark has an uppercase or lowercase mapping, does that get installed 
in \lccode and/or \uccode?

Also, there's a confusing typo ("can"?) in

- \lccode and \uccode for all of class "Lt" (title
  case letters) to the lower can upper case mappings
  (or if not given to the code point itself)

Should "can' be "and/or"?


Doug McKenna