Parse biblatex fields date, journaltitle and location in bibtex readers

[ms609]

I use Zotero with Better BibTeX to manage citations. Exported bib entries (and biblatex files in general) use date and journaltitle where BibTeX has year/month/day and journal, e.g.

@article{smith2020,
  author = {Smith, John},
  title = {A title},
  journaltitle = {Some Journal},
  date = {2020-02-02}
}

utils::bibentry() rejects such an Article (no journal, no year), so readBib() drops the entry with a warning under both direct = TRUE and direct = FALSE. Downstream, Rdpack's \insertCite then cannot cite it.

I've been manually replacing journaltitle with journal, and truncating date to year (and often forgetting to to this!). But as the same .bib works in R Markdown/Quarto vignettes (pandoc understands these fields), I wondered whether it might be possible for these fields to be supported here also.

I set Claude onto the task; this PR is the result. I've tested the code locally and it succeeds.

---

Change

process_ref() in src/common_bt_btd.c (shared by the bibtexin and bibtexdirectin readers) now normalises these biblatex fields, following pandoc's citeproc BibTeX reader (and biber):

• date: if it has the form [-]YYYY[-MM[-DD]], optionally followed by EDTF qualifiers (~ ? %), a time (T…) or a range (/…), it sets year, month (full month name, as for month = feb) and day, taking precedence over any year/month/day fields. An unparsable date (e.g. circa 2004) is ignored and year is used. For a range, only the start is used, since bibentry has no range.
• journaltitle takes precedence over journal.
• location supplies address if that is missing, except for @patent, where biblatex's location is the jurisdiction.

The biblatex fields themselves are kept (visible with direct = TRUE).

Checks

• New test and fixture inst/bib/biblatex_aliases.bib, run with both direct = TRUE and FALSE; it fails without the patch.
• Full test suite passes before and after.
• Compared readBib() output for every file in inst/bib/ before and after, with both values of direct: the only file whose output changes is biblatex-examples_sans_key_aksin.bib, which now returns 84 rather than 32 entries (direct = TRUE) and 70 rather than 17 (direct = FALSE). Nothing previously read changes except for added year/journal/address fields.
• Output for the test file agrees with pandoc --citeproc on year, month, journal and place.
• Compiles without warnings with -Wall -pedantic.
• Rdpack's test suite passes against the patched package.

Documented in ?readBib (Details) and NEWS.md.

🤖 Generated with Claude Code

[GeoBosh]

Many thanks.

I am still travelling but will deal with this at the beginning of October.