Citations with question mark not recognized

[liob]

Pandoc appears to have issues with citation keys containing question marks. This is actually a problem since Zotero exports keys containing question marks if no date is given.

citation_test.md:

Pandoc Citation Test
====================

Citations with questionmarks in their biblatex key do not work [@you_dont_see_me_????].

Without questionmark it works just fine [@now_you_do].

bibliography.bib:

@ARTICLE{you_dont_see_me_????,
  author = {No One},
  title = {You Don't See Me},
}

@ARTICLE{now_you_do,
  author = {No One},
  title = {You See Me},
}

pandoc --bibliography=bibliography.bib citation_test.md

pandoc-citeproc: reference you_dont_see_me_ not found

Pandoc Citation Test

Citations with questionmarks in their biblatex key do not work (????).

Without questionmark it works just fine (One).

One, No. “You See Me.”

[jgm]

Final punctuation is not allowed in keys. The reason is that
a final punctuation mark in an in-text citation might be intended
to be real punctuation: e.g.

Do you agree with the results of @smith2000?

[liob]

I see your point. However, as question marks, as well as some other punctuation marks, are valid key characters there should be a way of escaping. Maybe something on the lines of:

Do you agree with the results of @smith2000\??

That said, the practice of Zotero of using four question marks for a missing date is no benefit in terms of key differentiation. I will ask them to simply drop the question marks.

[jgm]

Any success convincing Zotero devs to change this?

[mpickering]

I don't think this was fully followed up.

[tarleb]

Should this be fixed in pandoc? If yes, the way to go would probably be to change citeKey in Text.Pandoc.Parsing in a way that allows keys to end with escaped punctuation characters.

[jgm]

I'm not keen on treating @foo? differently from @foo\? in the way I think you're suggesting. Backslash escapes should have a single meaning, and this would give them another meaning: namely, "count this as part of the citation key and not as a regular question mark."

Perhaps we could introduce an alternative syntax for author-in-text citations, e.g. [@@foo] == @foo but [@@foo?] is possible. But I'm not sure it's so important to support keys ending in arbitrary punctuation.