Looking for Eglot pop-up menu like functionality:

[zeta-00]

Greetings,

I just god Eglot working with Company, but, I was wondering if Eglot has equivalent functionality to LSP-UI, like a popup-menu, documentation, and so forth?

Or will I need enable some extra company feature to get this type of functionality with Eglot?

https://github.com/company-mode/company-quickhelp
^ This extra company-quickhelp package looks useful, but I want to check if Eglot has it's own built-in UI functionality to implement stuff like this?

Note: I'm transitioning from lsp-mode/lsp-ui to Eglot, so there's a lot I don't know and Eglot is still lacking in the documentation area. Eglot itself seems similar to lsp-mode, but I'm not sure what's the best way to get lsp-ui like functionality working with Eglot?

I'm confused about this, so I figured I'd ask here.

Thanks in advance for the help.

[trev-dev]

With eglot your choices are:

1. Eldoc

With this in mind you can look at packages that hook into Eldoc to "pop-up" information in places other than the mini-buffer.

There are two solutions that I have tried that work well.

1. https://repo.or.cz/eldoc-overlay.git - Eldoc Overlay. This one works well out of the box. Make sure to activate company before you activate eldoc-overlay. This is just as annoying as Eldoc, but it puts the obnoxious buffer-size changes next to your cursor instead 🥳
2. https://github.com/casouri/eldoc-box - My personal favorite, though, it only works well if you configure it just so:

   (setq eldoc-box-cleanup-interval 2
         eldoc-box-max-pixel-height 900
         eldoc-box-max-pixel-width 1500)

The max-pixels are up to your taste, but the defaults on most modern screens will cause lines to wrap obnoxiously early.

The eldoc-box-cleanup-interval is gosh-darn mandatory. Without it, eldoc-box will interrupt your one and only thread if you move around too quickly and it m-m-m-makes things -s-t-st-stutter. Keeping the box alive longer means no need to keep re-rendering the box.

Want to use the eldoc-box-hover-at-point-mode? Forget it! You may as well go back to LSP mode and lsp-ui and abandon any further hope for minimalism you had because the performance of this mode is abhorrent. Want to stop hiding the pop -over until you have enough curiosity to render one with eldoc-box-eglot-help-at-point? Forget it! It's broken.

---

Edit: Eldoc Box has gotten a lot better, as there are now working functions that call up the box on-demand. There are two separate commands for when you have Eglot, and when you do not:

(setq eldoc-echo-area-use-multiline-p nil
      eldoc-idle-delay 0.75)

(require 'eldoc-box)
(global-set-key (kbd "C-c i") #'eldoc-box-help-at-point)
(define-key eglot-mode-map (kbd "C-c I") #'eldoc-box-eglot-help-at-point)

Hope this helps.

[krisbalintona]

@trev-dev Regarding the annoying line wrapping in the eldoc-box frame, the key function to look at is eglot--format-markup I think. The line wrapping is caused because the documentation is sent as markdown and eglot uses markdown (of the Github flavor) to render it. The line wrapping issue is caused by how gfm-view-mode renders horizontal rules, i.e. "---".

I wrote the following workaround which replaces "---" with something else. In this case, I replaced it with a sequence of hyphen-like characters that should fill the width of the popup frame without causing wrapping:

  (defun kb/eglot--format-markup (markup)
    "Format MARKUP according to LSP's spec."
    (pcase-let ((`(,string ,mode)
                 (if (stringp markup) (list markup 'gfm-view-mode)
                   (list (plist-get markup :value)
                         (pcase (plist-get markup :kind)
                           ("markdown" 'gfm-view-mode)
                           ("plaintext" 'text-mode)
                           (_ major-mode))))))
      (with-temp-buffer
        (setq-local markdown-fontify-code-blocks-natively t)

        ;; Replace the horizontal rule, which is three hyphens in the markup,
        ;; with X number of hyphens-like characters, with X being enough to
        ;; cover the width of `eldoc-box-max-pixel-width'. We can't simply
        ;; replace with more hyphens since `gfm-view-mode' renders any set of
        ;; three hyphens as a horizontal rule
        (setq string (string-replace "---"
                                     (make-string (floor (/ eldoc-box-max-pixel-width (window-font-width))) ?⎺)
                                     string))

        (insert string)
        (let ((inhibit-message t)
              (message-log-max nil))
          (ignore-errors (delay-mode-hooks (funcall mode))))
        (font-lock-ensure)
        (string-trim (buffer-string)))))
  (advice-add 'eglot--format-markup :override #'kb/eglot--format-markup)

I tried looking at markdown-hr-strings as well since it seems relevant but I don't know much about markdown-mode so I settled with the workaround above instead. There should be some edge cases between font pixel widths but this should work most of the time for fixed-pitch fonts.

[cxa]

The hr problem is due to markdown-mode render it as the width as the window body:

https://github.com/jrblevin/markdown-mode/blob/master/markdown-mode.el#L3515

It's uncontrollable. So I just replace the --- to empty to workaround this problem:

  (defun cxa/filter-args/eglot--format-markup (args)
    (mapcar (lambda (markup)
	      (if (plistp markup)
		  (let* ((value (plist-get markup :value))
			 (kind (plist-get markup :kind))
			 (_ (string= kind "markdown"))
			 (value (string-replace "---" "" value)))
		    (plist-put markup :value value))
		markup))
	    args))

(advice-add 'eglot--format-markup :filter-args 'cxa/filter-args/eglot--format-markup)

[ambihelical]

Seems that "\n---\n" works better, less vertical space, probably safer too. Also had to change it a little for 28.1, plistp isn't defined. Thanks for this in any case.

@joaotavora Should eglot be doing this itself, at least as an optional filter? Any sort of child frame will display multiple lines of hyphens for horizontal rulers without it.

[ambihelical]

There is also a similar problem in markdown-mode independent of eglot due to text scaling.

jrblevin/markdown-mode#618

[trev-dev]

FYI I updated my original response to suit my newer experience with eldoc-box. #912 (comment)