Improve org-insert-link completion (was: [Bug] org-insert-link removes on one link from 2 added by org-store-link)

[Ihor Radchenko <yantar92@posteo.net>]

Samuel Wales <samologist@gmail.com> writes:

> link has already been stored is a bug in my case in that i can't just
> go to a header, grab it [whether rabbed bfere or not] and then paste
> it.  i surprise easily when the wrong link gets pasted.

This has been fixed already.

> in answer to a q by ihor, indeed puttig previously stored id liks as
> descriptions in front of all the prefixes woudl be useful to me, but
> idk who is doing the sorting, so idk whether it wold make a difference
> but if it dos then gret..]

Org is actually not supposed to control sorting. It is to be customized
by user via `completions-sort'.

What we can do instead is provide grouping metadata.

Below, I provide a simple demo on how it looks like.
However, the demo will only make a difference starting from Emacs 28
that has the necessary completion API.

(defun org--complete-links (string predicate flag)
  (let* ((links '(:type ("id:" "file:") :path ("/a/a/b" "file.org") :description ("foo" "barr" "baz")))
	 (all-links (append (plist-get links :type) (plist-get links :path) (plist-get links :description)))
         matches)
    (pcase flag
      (`nil (try-completion string all-links predicate))
      (`t (all-completions string all-links predicate))
      (`lambda (test-completion string all-links predicate))
      (`(boundaries . suffix) (completion-boundaries string all-links predicate suffix))
      (`metadata
       `(metadata
         (group-function
          .
	  (lambda (completion transform)
            (if transform completion
              (let ((links ',links))
		(cond
		 ((member completion (plist-get links :type)) "Link type")
		 ((member completion (plist-get links :path)) "Link path")
		 ((member completion (plist-get links :description)) "Link description")))))))))))


(completing-read "Test: " #'org--complete-links)

> it seems org-insert-=inki is overloaded.  one use case says insert a
> previously stored link.  the other says insert a brand new link which
> i will now specify.  might it be useful to separate those two
> functions?

I do not see why it is overloaded. The last stored link is used as
default completion option, which is a common practice.

You can also use C-u 1 C-c C-M-l to insert the last stored link.
Or just C-c C-M-l.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>