;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/bibtex/bibtex-field.el
;;
;; test here:
;;   https://dataswamp.org/~incal/books/books.bib

(require 'cl-lib)

(defun bibtex-prev-field ()
  (interactive)
  (cl-labels ((search-prev ()
                (when (re-search-backward "=\\|@" nil t)
                  (let ((eol (line-end-position)))
                    (unless (re-search-forward "{" eol t)
                      (forward-char 2) )))
                (point) ))
    (when (= (point) (search-prev))
      (let ((beg (point)))
        (beginning-of-line)
        (when (= (point) (search-prev))
          (goto-char beg) )))))

(provide 'bibtex-field)