// appears in
every single URL. It might be possible to have the
parser recognise urls and automatically escape the token, but it's a
definite complication.
No it's not. Or at least, not much of one. If it immediately follows
\W[a-z]+: then you assume it's part of a URL. That will make it
difficult to impossible to italicize the domain name in a URL, but you
know? I can live with that. :-)
It's a complication, just a resolvable one. Part of the idea of
sorting out the grammar is to make the syntax make sense and not be
full of special cases where the parser makes it up as it goes along.
In this case, it may well be worth making the very safe guess, but
it's a complication that has to be considered. (You could still
italicise a domain name: http:////www.domain.com///index.html The only
question is whether or not the / between the domain name and the file
name is in italics or not...)