Biblatex with verify ISBN

[Emanuel Berg]

I just did some work integrating my Biblatex and ISBN
verify stuff, so now when the autokey is inserted it
actually _isn't_ if the ISBN doesn't check out.

Also featuring a brand new `error' message if the
ISBN has any other number of digits than 10 or 13,
since there are no such ISBNs.

Last, there is an error message if the check digit
doesn't check out - seemingly the point of the
software to begin with, right? :)

ISBN verify:
  https://dataswamp.org/~incal/emacs-init/isbn-verify.el (lines 71-83)

Biblatex:
  https://dataswamp.org/~incal/emacs-init/my-bibtex.el (l. 38-42)

entries to try on:
  https://dataswamp.org/~incal/books/books.bib

keep it real time

-- 
underground experts united
http://user.it.uu.se/~embe8573
https://dataswamp.org/~incal