[XeTeX] velthuis tranliteration scheme and virama

[François Patte]

Le 2025-02-07 17:42, Zdenek Wagner a écrit :
> Bonjour,
> 
> the problem is that catcodes are examined and interpreted upon input
> but TECkit mapping occurs during output, thus special characters will
> never go that far. If possible, you can change the catcodes only
> locally within a block where you need them. I admit that it can be too
> cumbersome thus another possibility is to do:
> 
> \def\subscript{_}
> \catcode`\_=11

Thank you for this.

> And if you use Linux, you can use my keyboard and write directly in
> Devanagari, I made it to be as much similar to the Velthuis system as
> possible.

Thank you, but I still remain to the use of Velthuis transliteration :
1- I have 30 year old files, when devanagari was available through the 
devnag preprocessor
2- It is easy to type with this system using a simple 7-bits ascii 
keyboard and it is easy to share a file with other people.
3- From one file with this code, I can output a pdf in devanagari, in 
roman transliteration and grantha by the way of map/tec mechanism.

BTW I have two map files "velthuis-romanized.map" and 
"velthuis-grantha.map" which could be of some interest for people and 
which are not available through TeX distributions.

Thank you again.

F.P.

> <francois.patte at mi.parisdescartes.fr> napsal:
>> 
>> Bonjour,
>> 
>> I am facing a problem with virama while using the velthuis
>> tranliteration scheme : according the velthuis-sanskrit.map file, 
>> virama
>> is mapped to "&" and "_".
>> 
>> I use FreeSerif fonts and some ligatures can be acceeded using a 
>> virama
>> eg.:
>> 
>> r+r-vocalic (r.r) gives: रृ or
>> r+virama+r-vocalic (r&.r) gives: र्ऋ
>> 
>> To get the second ligature (र्ऋ), which I prefer, I have to change the
>> catcode of "&" or"_":
>> 
>> \catcode`\&=11\relax or \catcode`\_=11\relax
>> 
>> Both cases have one major disadvantage: for "&", I can't use tabular
>> environments, for "_"; I can't use mathematical mode...
>> 
>> Is there a way around this problem? Is there a feature in fontspec
>> allowing the use of alternative ligatures?
>> 
>> Or do I have to map the virama to an other character (which one?) in
>> velthuis-sanskrit.map file?
>> 
>> Thank you.
>> 
>> Regards

-- 
François Patte
UFR de mathématiques et informatique
Laboratoire CNRS MAP5, UMR 8145
Université Paris Descartes
45, rue des Saints Pères
F-75270 Paris Cedex 06
Tél. +33 (0)6 7892 5822
http://www.math-info.univ-paris5.fr/~patte