Currently 'font-ota.lua' hard codes the Arabic shaping properties,and it
doesn't seem to be complete  (e.g. the ڤ as in أڤاست is not joined), I
think such information belong to 'char-def.lua' and should be derived
from UCD, which provide 'ArabicShaping.txt[1]', covering Arabic, Syriac
and N'Ko scripts which all need the same shaping as Arabic.

[1]http://unicode.org/Public/5.1.0/ucd/ArabicShaping.txt

Regards,
 Khaled


-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer