bug#64972: bibtex-autokey-get-year does not recognize biblatex date ranges

[Eli Zaretskii]

> From: Roland Winkler <winkler@gnu.org>
> Cc: Gustavo Barros <gusbrs.2016@gmail.com>,  64972@debbugs.gnu.org
> Date: Tue, 22 Aug 2023 19:09:31 -0500
> 
> On Sat, Aug 05 2023, Eli Zaretskii wrote:
> >>       date         = {2020-10/2020-12},
> >> 
> >> Results in user-error "Year or date field ‘2020-10/2020-12’ invalid".
> >> 
> >> The "date" field, however, is valid `biblatex' syntax for a date
> >> range, according to the section "2.3.8 Date and Time Specifications"
> >> of `biblatex's manual.
> >
> > Roland, any comments?
> 
> biblatex permits dates and date ranges according to ISO 8601.
> 
> The problem in bibtex-autokey-get-year arises because iso8601-valid-p
> believes that the string "2020-10/2020-12" is not valid according to
> ISO 8601, though iso8601-parse-interval parses that string correctly.
> 
> So it seems to me that this problem requires, first of all, some changes
> in iso8601.el.  Who is familiar with this code and can possibly make
> suggestions?

I hope Paul (CC'ed) will.