Temporary display line numbers

[manuel-uberti]

Hi,

first of all thanks for this great package. I installed it from MELPA like this:

(use-package goto-line-preview          ; Preview line on `goto-line'
  :ensure t
  :bind ([remap goto-line] . goto-line-preview-goto-line))

Since I don't have line numbers permanently enabled, would it be possible to display line numbers only on M-g g?

I did use to have something like this before:

(defun mu-goto-line-with-line-numbers ()
  "Display line numbers temporarily when using `goto-line'."
  (interactive)
  (let ((display-line-numbers t))
    (call-interactively #'goto-line)))

But it doesn't work if I replace #'goto-line with #'goto-line-preview-goto-line.

[waymondo]

Once I discovered this package this was my first suggestion as well.

[purcell]

I'd be a bit wary of trying to make this work reliably by changing this package, because of linum vs. nlinum vs. display-line-numbers-mode, so I would strongly discourage this. However, making it possible to do such a thing in user config is reasonable.

I imagine that an advice version of the above code might work, but I haven't tested it.

[waymondo]

In my setup, here's what I've been using for the behavior @manuel-uberti is describing:

(defun goto-line-with-line-numbers ()
    (interactive)
    (let ((not-already-showing (or (not (boundp 'display-line-numbers-mode))
                                          (eq nil display-line-numbers-mode))))
      (display-line-numbers-mode 1)
      (unwind-protect
          (call-interactively #'goto-line)
        (when not-already-showing
          (display-line-numbers-mode -1))))))

Lexically binding display-line-numbers is a nice cleaner trick for achieving what I was doing.

Though with my solution, you can easily swap out display-line-numbers-mode with linum and the same behavior happens. I haven't tested it with nlinum, but I'm assuming it could still work.

My general idea of how this feature could look like would be an optional defcustom for goto-line-preview-ensure-line-number-mode. If it's defined, it ensures that this symbol's mode would be engaged for the duration goto-line-preview-goto-line is executing. It it wasn't enabled prior to goto-line-preview-goto-line, it could be ensured to get unset via unwind-protect.

[purcell]

Or perhaps, more idiomatically, a pair of hooks that are run when input starts and the command exits.

[manuel-uberti]

I was thinking about hooks as well, and I did try to configure this behaviour via a hook but with no effect.

[purcell]

I was thinking about hooks as well, and I did try to configure this behaviour via a hook but with no effect.

Yeah, you'd need hooks that aren't yet there.

[manuel-uberti]

I guess we can close this, following @purcell's suggestion solves the problem.