Bibliography: support CSL?

[Omikhleia]

Some of the issues regarding bibliographies (eg. #2027, #2049) are hampered by the fact that SILE has it's own-made Chicago style implementation. I know of at least one similar attempt at implementing another style on the same grounds (@jodros 's ABNT)

Question 1. What would be SILE's position on deprecating these hand-made styles, and switch to CSL?

• Proper localization is provided by CSL locales
• Lots of standard styles have a CSL implementation, incl. various versions of the Chicago style.

Question 2. Would SILE be ok with its own implementation of (a decent subset) of CSL in Lua?

• CSL is not that hard of a schema (compared, say, to USX and all its implications (#1398)...
• The alternative is to use an existing CSL processor (but it is not that easier to hook back into SILE and it's far less fun IMHO)

[Omikhleia]

Note on license issue: CSL local and styles files are CC-BY-SA. AKAIK, it means we can't just vendor them with SILE (MIT) -- but submodules, or a build dependency, could be acceptable.

[jodros]

I know of at least one similar attempt at implementing another style on the same grounds (@jodros 's ABNT)

That file is only a draft, since I din't understand well how to use...

BTW I'm glad to see that a refactor of bibliography is underway, I hope I can help.

[Omikhleia]

Self-assigning: I'm experimenting a CSL engine (the 80% easy are reached, the question is how to get the 20% difficult right, lol). (Just for you to know -- It might take a bit of time, and the points raised above are valid however this goes)

[Omikhleia]

Teaser.

Our legacy Chicago style vs. CSL "author-date" Chicago style for the exact same bibtex entry...

[Omikhleia]

Teaser no. 2

Same bibtex entry, but French CSL locale and French "author-date" Chicago CSL style. Yay, honoring gender for the ordinals :)