Get bibtex key from helm-bibtex

Question

I would like to get the bibtex key of references in my .bib database as a string via helm-bibtex.

(defun get-bibtex-key ()
  (interactive)
  (with-temp-buffer
    (helm-bibtex)
    (if (string-prefix-p "cite" (buffer-string))
        (substring (buffer-string) 5) ;; Remove "cite: " from string.
      (buffer-string))
    (buffer-string)))

The code above correctly returns the desired value, but inserts text into the current buffer instead of storing its value within the get-bibtex-key function-variable as a string, which makes further deployment such as this impossible:

(bibtex-completion-get-entry (get-bibtex-key))

The above code when run just dumps the value returned by (get-bibtex-key) into the current buffer.

How can I get output from (helm-bibtex) behave like the code below?

(with-temp-buffer
  (insert "Hi!")
  (buffer-string))

Answer 1

You can also get the keys using helm-marked-candidates:

(defun get-bibtex-key (_)
  (let ((keys (helm-marked-candidates)))
    (print keys)))

(helm-add-action-to-source "Get bibtex keys" 'get-bibtex-key helm-source-bibtex 0)

Then:

1. M-x helm-bibtex
2. M-a
3. RET

Answer 2

If I understand correctly, you can use the (bibtex-completion-candidates) function, which returns a list of bibtex items. You then get the list containing the "=key=" string using assoc, taking the cdr (last) element of the alist which is the citation key. Finally pass this list of keys through completing-read so you can select one from the list, returning it as a string:

(defun get-bibtex-key ()
  (interactive)
  (completing-read "Citation key: "
                  (mapcar #'(lambda (x) (cdr (assoc "=key=" x)))
                          (bibtex-completion-candidates))))