How to convert a BibTeX entry into formatted string?

Question

I'd like to be able to export BibTeX entries as (flexibly formatted) strings.

For example, a BibTeX entry like this one:

@Article{Chomsky:59,
  author    = {Noam Chomsky},
  title     = {On Certain Formal Properties of Grammars},
  year      = {1959},
  volume    = {2},
  pages     = {137--167},
  journal   = {Information and Control}
}

Should be converted into the following string:

Chomsky, Noam. 1959. On Certain Formal Properties of Grammars. Information and Control 2. 137--167. 

I used to manage my BibTeX database with JabRef which lets you customize exports. But I haven't seen something similar in Emacs/bibtex.el.

Answer 1

The org-ref package contains this functionality. Contrary to the name, org-ref has a lot of functionality outside of org mode. Take a look at the function org-ref-format-bibtex-entry. It also integrates this into helm-bibtex, so if you get everything set up correctly, you can call helm-bibtex, mark the citations you want, then hit f7 which inserts a formatted list.

EDIT:

If you didn't want to add a whole package with lots of dependencies, you can write your own function. Here's an example to illustrate:

(defun bibtex-format-entry-to-string ()
 "Format bibtex entry under point to a string."
 (interactive)
  (save-excursion
    (bibtex-beginning-of-entry)
    (let ((authors (bibtex-text-in-field "author"))
          (year (bibtex-text-in-field "year"))
          (title (bibtex-text-in-field "title")))
      (format "%s, %s, %s" authors year title))))

Answer 2

I've eventually found a very flexible way to achieve this using helm-bibtex and citeproc.el, adding just the following code (taken from here):

(defvar helm-bibtex-csl-style "~/.emacs.d/csl/unified-style-sheet-for-linguistics.csl")

(defvar helm-bibtex-csl-locale-dir "~/.emacs.d/csl")

(defun helm-bibtex-insert-citeproc-reference (_candidate)
  (let* ((locale-getter (citeproc-locale-getter-from-dir helm-bibtex-csl-locale-dir))
         (item-getter (citeproc-itemgetter-from-bibtex helm-bibtex-bibliography))
         (proc (citeproc-create helm-bibtex-csl-style item-getter locale-getter))
         (cites (mapcar (lambda (x) (citeproc-citation-create :cites `(((id . ,x)))))
                        (helm-marked-candidates))))
    (citeproc-append-citations cites proc)
    (insert (car (citeproc-render-bib proc 'plain)))))

(helm-add-action-to-source "Insert citeproc-formatted reference" 'helm-bibtex-insert-citeproc-reference helm-source-bibtex)

This method requires that you provide a CSL file and specify its path in helm-bibtex-csl-style and helm-bibtex-csl-locale-dir. There exist CSL files for virtually every formatting style. You can choose and download them conveniently here.