[luatex] Kerning: when does it not work?

[Ulrike Fischer]

Am Thu, 5 May 2011 09:06:19 +0200 schrieb Heilmann, Till A.:

> Well, there are some problems with Paul's code, after all: The  
> underscore character _ cannot be part of a URL *if* it occurs inside  
> a footnote (see below). I have not checked for errors with other  
> characters yet.

The \url command tries to adjust the catcodes (with the
\let\do\makeother \dospecials line) but can't do it if the catcode
is already fixed when used in the argument of another command. 

You can change the catcodetable additionally in the \setbox command:

\setbox\urlbox=\hbox{\directlua{tex.sprint(-2,"#1")}}%

It will need some testing to decide which catcode table is suitable
(for the test I simply took -2 where everything has catcode 12).

But it will not solve all problems in \footnote: % and \ will still
not work. So if you want to use url's in argument of other commands
you will probably still need an \urldef-command like with the
standard \url.

-- 
Ulrike Fischer