Add instructions for emacs with lsp-mode

[alanz]

Documentation change only

[stew]

When I try to add this stuff to my emacs inititalization I get:

Symbol's function definition is void: lsp-register-client

[alanz]

lsp-register-client is defined in lsp-mode. I guess I should add

(use-package lsp-mode
)

[stew]

Now when I open a .u file I get this message:

LSP :: The following servers support current file but do not have automatic installation: unisonlang
You may find the installation instructions at https://emacs-lsp.github.io/lsp-mode/page/languages.
(If you have already installed the server check *lsp-log*).

[alanz]

As per the overall language server instructions, you do not start it as normal, just connect to it.

So what I do is

M-x term
~/unisonlang/ucm

This starts a ucm session, which also listens on port 5757.

Then open a xxx.u file in the same directory you started ucm, and it should work. You can also do lsp-workspace-restart once you start up ucm

[stew]

Yeah, I still get this error whenever it tries to start lsp-mode in a .u buffer. even if ucm is running.

lsp-mode DOES work for other language servers, and LSP is currently working for me with unison using vscode

[acowley]

I ran into the same situation as stew when following the instructions in this PR.

The approach shown below works in that I see type check errors, but the type information for local variables is not good (e.g. for the Unison hello world program, the use of the local variable name shows popups for Author.name and CopyrightHolder.name). I also get The connected server(s) does not support method textDocument/completion. when trying to complete names. If those are all expected, I can open a PR with this approach (which I modeled on lsp-gdscript).

(lsp-register-client
   (make-lsp-client
    :language-id "unisonlang"
    :new-connection 
    (list
     :connect (lambda (filter sentinel name _environment-fn _workspace)
                (let* ((host "localhost")
                       (port 5757)
                       (tcp-proc (lsp--open-network-stream host port (concat name "::tcp"))))

                  (set-process-query-on-exit-flag tcp-proc nil)
                  (set-process-filter tcp-proc filter)
                  (set-process-sentinel tcp-proc sentinel)
                  (cons tcp-proc tcp-proc)))
     :test? (lambda () t))
    :major-modes '(unisonlang-mode)
    :server-id 'unisonlang
    ))

[zetashift]

I don't see the textDocument/completion errors, but the type information for local variables indeed is off:

(my cursor is on the "name" variable)

My config:

(use-package unisonlang-mode
  :mode "\\.u\\'"
  :ensure t
  :config
  
  (add-hook 'unisonlang-mode-hook 'lsp-deferred)
  (with-eval-after-load 'lsp-mode
    (add-to-list 'lsp-language-id-configuration
         '(unisonlang-mode . "unisonlang"))
    (setq-local lsp-tcp-connection-timeout 10)
    (lsp-register-client
     (make-lsp-client
      :new-connection
      (list
       :connect (lambda (filter sentinel name _environment-fn _workspace)
                  (let* ((host "localhost")
             (port 5757)
             (tcp-proc (lsp--open-network-stream host port (concat name "::tcp"))))

                    (set-process-query-on-exit-flag tcp-proc nil)
                    (set-process-filter tcp-proc filter)
                    (set-process-sentinel tcp-proc sentinel)
                    (cons tcp-proc tcp-proc)))
       :test? (lambda () t))
      :activation-fn (lsp-activate-on "unisonlang")
      :server-id 'unisonlang))))

[zetashift]

I don't know if this should be a new issue but VSCode reports the same actually:

[sellout]

I just put up #4922, which does this for Eglot instead of lsp-mode. Mostly because it’s simpler.