Feature: group bibliography entries by year with section headings

[michaelaye]

Problem

When rendering a full bibliography (e.g. with nocite: '@*' for a publications page), all entries appear as a flat list. For academic CVs and publication pages, it's standard to group entries by year with reverse-chronological headings:

## 2024
- Paper A ...
- Paper B ...

## 2023
- Paper C ...

There is no built-in way to do this. Users must write Lua filters that:

1. Disable citeproc (citeproc: false)
2. Manually call pandoc.utils.citeproc(doc)
3. Walk the refs div, extract years from pandoc.utils.references(doc), group entries, and insert headers

Proposed solution

A YAML option to enable year grouping:

bibliography: refs.bib
nocite: '@*'
bibliography-group-by: year
bibliography-sort: date-desc

This would instruct citeproc to insert heading elements (H2 by default) between year groups, sorted newest-first.

Alternatives considered

• Lua filter with pandoc.utils.citeproc() (current workaround; requires disabling built-in citeproc)
• Multiple nocite sections per year (manual maintenance, breaks on new publications)
• Section-bibliographies filter (groups by document section, not by publication year)

[michaelaye]

let me know if you want a working Lua filter code.

[mcanouil]

For reference, existing extensions working with citations/bibliography:

• https://github.com/bcdavasconcelos/citetools
• https://github.com/dialoa/recursive-citeproc
• https://github.com/pandoc-ext/multibib
• https://github.com/pandoc-ext/section-bibliographies

[michaelaye]

I considered briefly submitting this to section-bibliographies, but the ideas are orthogonal: Those are bibs per section, mine is section one bib on the same page by year, with TOC. So I added another extension: https://github.com/michaelaye/chronobib

[mcanouil]

Feel free to submit your extensions to Quarto website or my extensions listing for use with Quarto Wizard.