Add `smart-jump-go-other-window`

[mnewt]

What's the best way to implement a version of smart-jump-go that pops open in a new/other window, like xref-find-definitions-other-window? Should :before-jump-fn be used, or would smart-jump-run need to be modified?

Thanks!

[jojojames]

You can probably define something like this that uses the other- type functions.

(defvar smart-jump-xref-fallback
  '(
    :jump-fn xref-find-definitions
    :pop-fn xref-pop-marker-stack
    :refs-fn xref-find-references
    :should-jump t
    :heuristic error
    :async nil
    :order 1000
    )
  "Xref fallback to use when no other :jump-fn mechanism succeeded.")

I'm not sure how it'd be done generically though (or even feasible).

[mnewt]

How about this? It works for me.

(defun smart-jump-go-other-window (&optional smart-list continue)
    "Show the function/variable declartion for thing at point in another window.

SMART-LIST will be set (or nil) if this is a continuation of a
previous jump.

CONTINUE will be non nil if this is a continuation of a previous jump."
    (interactive)
    (let ((old (current-buffer)))
      (smart-jump-go smart-list continue)
      (let ((new (current-buffer)))
        ;; If old and new are the same then `xref' has popped up another window
        ;; listing multiple definitions and we bail.
        (unless (eq new old)
          (switch-to-buffer old)
          (switch-to-buffer-other-window new)))))

Only caveat is if xref finds multiple definitions then xref opens another window midway through the process and there doesn't seem to be a good way to react to that so the command just gives up. A way around that would be to use a lower level xref function to actually get a list of references like this (using use-package as an example that returns multiple references)

(funcall (xref--create-fetcher 'use-package 'definitions 'use-package))

And then use completing-read to prompt the user rather than the popup window

That would require re-plumbing the xref-find-definitions fallback but shouldn't be too terrible to implement.

Are you interested in a PR along those lines? Or have other suggestions?