"Bruce D'Arcus" <bdar...@gmail.com> writes: > I'm not super sure of the details around, for example, bibtex, but > this post seems to be helpful to check against for the details? > > https://tex.stackexchange.com/questions/388500/what-is-valid-as-a-biblatex-entry-key/388652#388652
Oh my! You're reviving a 6 years old thread[¹]! Basically, current syntax is inherited from a previous citation specification allowing shortcuts: @key instead of [cite:@key]. Since these shortcuts do not exist anymore, we don't need to be so careful about characters allowed in a key. The only one being dangerous is the semicolon, since it is used to separate keys in a citation reference. Closing square bracket could also be problematic if it is not paired properly. So, to be on a safe side, anything beside space, semicolon and square brackets are fine. However, allowing anything means some keys will not be compatible with some bibliography formats. For example, I doubt BibTeX would appreciate a percent character in a key. OTOH, we can put the burden of the user's shoulders. So... let's get liberal and say a key must match: (rx "@" (one-or-more (any word "-.:?!`'/*@+|()<>&_^$#%&~"))) Nothing bad could happen, right? [¹] https://lists.gnu.org/archive/html/emacs-orgmode/2015-03/msg00131.html -- Nicolas Goaziou