[luatex] on some special glyph nodes

[Arthur Reutenauer]

> In order to typeset program code, I often need the ASCII variants of
> single quotes because "typograpic quotes" are sometimes confusing.

  Yes, that's understandable.

> What is the best way to achieve this with LuaTeX?

  I don't know.  It doesn't seem to me that there is a package out there
to do just that, but it shouldn't be hard to write one.

> Does it mean that the U+2019 slot is empty in the font the recipient
> is using?

  No, it means that U+2019 gets converted somewhere down the way, and
sometimes gets corrupted.  You must have seen that: the resulting email
contains either a question mark, the Unicode "not a character" character
(U+FFFD), or even something else.  To simply not display the character
would actually not be that bad.

  Of course the situation is improving, but it's enough for one link of
the chain to introduce errors to get a bad end result, and it's
particularly tricky to make a choice in emails because it depends on a
lot of factors at the other end of the chain (the email agent the
recipient(s) use, etc.)  Just the other day, I wrote an email to a
mailing list that included the British pound sign (£), which is part of
latin-1.  My mailer (mutt) sent out the email as latin-1, because I've
configured it to do so (latin-1 if possible, UTF-8 otherwise), and when
it came back to me (since I was subscribed to the mailing list I was
posting to), it came out, in UTF-8, as a capital Polish slashed L (Ł).
Very disturbing, and the mailing list is managed by Google Groups, which
- one would think - should be able to handle that kind of things
properly.

	Arthur