[XeTeX] XeTeX (/not/ XeLaTeX) : Marginal kerning, font protrusion, hyperlinks

[Philip Taylor]

On 25/03/2014 09:03, I write (to XeTeX-Bounces, not to the correct list
address) the message below.  Ross Moore kindly offered an off-list
answer, but basically that was suggesting to use the XeLaTeX interface
to the features in which I was interested and to use TeX's debugging
tools to try to ascertain what was going on at the primitive level;
in the case of hyperlinks, I failed to achieve this (see below).

I then discovered (to my chagrin) that I had asked a very similar
question on 04/10/2012 09:06, and Jonathan Kew had kindly responded

> The clues you're looking for can be found in the archives of this list:
> see http://tug.org/pipermail/xetex/2010-May/016465.html.

Jonathan was (of course) perfectly correct in that clues could indeed
be found in the message to which he refers, but there seems a more
important question which remains unresolved :

Why are these key XeTeX primitives (\XeTeXprotrudechars, \rpcode, etc)
not documented in /The XƎTEX reference guide/ ?   Will, Khaled,
Jonathan :  can you comment on this, and will these (and any other
currently undocumented primitives) be documented in the version of
/The XƎTEX reference guide/ which accompanies TeX Live 2014 ?

As regards the hyperlink question, I still remain totally unclear
how this can be addressed at the primitive level; I have
successfully embedded hyperlinks using "eplain.tex", but that
has very undesirable side-effects and I prefer not to be
dependent on auxilliary libraries; could anyone please tell me
how hyperlinks can be successfully created in raw XeTeX source
code ?

Many thanks in advance :
Philip Taylor
--------

> My sincere apologies for asking what may well be a couple of FAQs, but
> ever increasingly any attempt to search for information concerning
> TeX, PdfTeX or XeTeX returns information relevant only to LaTeX,
> PdfLaTeX or XeLaTeX [1].
>
> So, that said, could some kind person please remind me how to
>
> (a) embed hyperlinks in XeTeX source
> (b) enable character protrusion and/or marginal kerning (ditto).
>
> The "and/or" is because I am not clear whether they are the same thing.
>
> The document returned by "TeXdoc XeTeX", which commences
>
>> The XƎTEX reference guide
>> Will Robertson Khaled Hosny
>> May 21, 2013
>
> does not contain any mention of any of these features.
>
> Many thanks in advance :
> Philip Taylor
> --------
> [1] "Use language like a surgeon's scalpel, not like a chainsaw",
> wrote someone with whom I very strongly agree.  If only those
> seeking information concerning LaTeX, PdfLaTeX or XeTeX could
> use those words in their questions, rather than omitting the
> vital "La" element, search engines such as Google would be far
> more effective in returning the information that I seek rather
> than (as now) a great deal of information that is completely
> irrelevant.