Posts tagged "lsp":

Orderless completion in lsp-mode

If you, like me, are using corfu to get in-buffer completion and extend it with orderless to make it even more powerful, you might have noticed that you lose the orderless style as soon as you enter lsp-mode.

My setup of orderless looks like this

(use-package orderless
  :custom
  (orderless-matching-styles '(orderless-literal orderless-regexp orderless-flex))
  (completion-styles '(orderless partial-completion basic))
  (completion-category-defaults nil)
  (completion-category-overrides '((file (styles partial-completion)))))

which basically turns on orderless style for all things except when completing filenames.

It turns out that lsp-mode messes around with completion-category-defaults and when entering lsp-mode this code here adds a setting for 'lsp-capf. Unfortunately there seems to be no way to prevent lsp-mode from doing this so the only option is to fix it up afterwards. Luckily there's a hook for running code after the completion for lsp-mode is set up, lsp-completion-mode-hook. Adding the following function to it makes sure I now get to enjoy orderless also when writing code.

(lambda ()
  (setq-local completion-category-defaults
              (assoc-delete-all 'lsp-capf completion-category-defaults)))

Haskell, ghcide, and Spacemacs

The other day I read Chris Penner's post on Haskell IDE Support and thought I'd make an attempt to use it with Spacemacs.

After running stack build hie-bios ghcide haskell-lsp --copy-compiler-tool I had a look at the instructions on using haskell-ide-engine with Spacemacs. After a bit of trial and error I came up with these changes to my ~/.spacemacs:

(defun dotspacemacs/layers ()
  (setq-default
   dotspacemacs-configuration-layers
   '(
    ...
    lsp
    (haskell :variables
             haskell-completion-backend 'lsp
             )
    ...)
  )
)

(defun dotspacemacs/user-config ()
  (setq lsp-haskell-process-args-hie '("exec" "ghcide" "--" "--lsp")
        lsp-haskell-process-path-hie "stack"
        lsp-haskell-process-wrapper-function (lambda (argv) (cons (car argv) (cddr argv)))
        )
  (add-hook 'haskell-mode-hook
            #'lsp))

The slightly weird looking lsp-haskell-process-wrapper-function is removing the pesky --lsp inserted by this line.

That seems to work. Though I have to say I'm not ready to switch from intero just yet. Two things in particular didn't work with =ghcide=/LSP:

1. Switching from one the Main.hs in one executable to the Main.hs of another executable in the same project didn't work as expected – I had hints and types in the first, but nothing in the second.
2. Jump to the definition of a function defined in the package didn't work – I'm not willing to use GNU GLOBAL or some other source tagging system.