John MacFarlane, the developper of Pandoc, has released a new Citeproc
that generates citations and bibliographies using CSL style files (CSL=
citation style language). While it is written in Haskell and while it's
primarily intended for use with Pandoc, it can also be used in other
contexts. Provided with a JSON encoded list of references via stdin, it
can produce formatted output.

The man page of the new citeproc executable, for those who are interested:

https://github.com/jgm/citeproc/blob/master/man/citeproc.1.md

I know that ConTeXt has its own infrastructure to format bibliographies
and citations, but, given the enormous amount of available styles in
CSL, I nevertheless think that this could be a worthwile addition. What
would be necessary to make such a toll usable with ConTeXt? How
complicated would that be?

In principle, this should be trivial. [...]

Note that this scheme has a few drawbacks: [...] But I do agree that it will provide us with the ability to use the large number CSL styles.

Of course, a better option will be write a CSL processor in Lua, but that is a lot of tedious (but relatively simple) task. I wonder if there is already a CSL processor written in Lua.