Good morning Thành -- I have for some time been trying to get to the bottom of the mysterious new primitives in XeTeX that include \XeTeXprotrudechars, \rpcode, etc. The only "documentation" of these is a brief e-mail from JK dated Mon May 3 01:12:46 CEST 2010 :
http://tug.org/pipermail/xetex/2010-May/016465.html in which he mentions that they have been added. Despite the fact that they have therefore been around for about four years, they are still not documented in /The XƎTEX reference guide/, and Khaled today wrote :
From me: simply because I know near nothing about them.
Vafa then noted :
If I recall correctly, Hàn Thế Thành added these primitives to XeTeX; therefore he knows them best.
and so I am pursuing it with you. Are you able to point me at any formal documentation for this set of primitives to which I can refer Khaled, Will et al., in the hopes that they will finally be documented for TeX Live 2014, and are you also aware of any documentation discussing how hyperlinks can be embedded using XeTeX, another apparently undocumented feature that is successfully exploited by "hyperref", "eplain", etc., yet for which no primitive-level documentation seems to exist. ** Phil. -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex