bug#36167: [PATCH] Replace manually crafted hex regexes with [[:xdigit:]]

[Eli Zaretskii]

> Date: Tue, 11 Jun 2019 09:50:24 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 36167@debbugs.gnu.org, Konstantin Kharlamov <hi-angel@yandex.ru>
> 
> > [0-9A-Fa-f] still has one advantage: the reader, and the
> > writer, know exactly which characters are included without looking it up. 
> > For
> > example:
> > 
> > - whether upper case, lower case, or both are accepted
> > - whether non-ascii digits are accepted (included in [:digit:] on many
> > platforms)
> 
> +1.  At least the doc for [:digit:] should say exactly
> what it matches.  Then it'll be clear for readers and
> writers.

Isn't it clear already?  Here's what the documentation says now:

  ‘[:digit:]’
       This matches ‘0’ through ‘9’.  Thus, ‘[-+[:digit:]]’ matches any
       digit, as well as ‘+’ and ‘-’.

Is anything missing here?  Where did the question about non-ASCII
digits come from, given this text?