Merge pull request #1540 from TOTBWF/lsp-fsharp

lang/fsharp: add LSP support

modules/lang/fsharp/README.org

@@ -12,6 +12,7 @@
   - [[#mono][Mono]]
     - [[#osx][OSX]]
     - [[#arch-linux][Arch Linux]]
+  - [[#lsp][LSP]]
 - [[#features][Features]]
 - [[#configuration][Configuration]]
 - [[#troubleshooting][Troubleshooting]]
@@ -28,22 +29,25 @@ This module adds [[https://fsharp.org/][F#]] support.
 + Syntax checking
 
 ** Module Flags
-This module provides no flags.
-
++ =+lsp= Enables lsp-fsharp (this requires ~:tools lsp~ to be enabled).
 ** Plugins
 + [[https://github.com/fsharp/emacs-fsharp-mod+e][fsharp-mode]]
++ =+lsp=
+  + [[https://github.com/emacs-lsp/lsp-mode/blob/master/lsp-fsharp.el][lsp-fsharp]]
 ** Hacks
 None so far.
 
 * Prerequisites
 ** Mono
-To get code completion/syntax checking, you will need to install [[https://www.mono-project.com/][mono]].
+To get code completion/syntax checking when not using lsp, you will need to install [[https://www.mono-project.com/][mono]].
 *** OSX
 Do *NOT* install mono via brew. See this [[https://github.com/fsharp/FsAutoComplete/issues/331][issue]].
 *** Arch Linux
 #+BEGIN_SRC sh
 sudo pacman -S mono
 #+END_SRC
+** LSP
+The language server is automatically installed by [[https://github.com/emacs-lsp/lsp-mode/blob/master/lsp-fsharp.el][lsp-fsharp]].
 * Features
 An in-depth list of features, how to use them, and their dependencies.
 

modules/lang/fsharp/config.el

@@ -1,14 +1,20 @@
 ;;; lang/fsharp/config.el -*- lexical-binding: t; -*-
 
 (after! fsharp-mode
-  (setq fsharp-ac-use-popup nil) ; Use a buffer for docs rather than a pop-up
-  (set-lookup-handlers! 'fsharp-mode :async t :definition #'fsharp-ac/gotodefn-at-point)
-  (set-company-backend! 'fsharp-mode 'fsharp-ac/company-backend)
+  (if (featurep! +lsp)
+      (progn
+        (setq fsharp-ac-intellisense-enabled nil)
+        (setq lsp-fsharp-server-install-dir (concat doom-etc-dir "fsautocomplete/"))
+        (add-hook 'fsharp-mode-local-vars-hook #'lsp!))
+    (setq fsharp-ac-use-popup nil) ; Use a buffer for docs rather than a pop-up
+    (set-lookup-handlers! 'fsharp-mode :async t :definition #'fsharp-ac/gotodefn-at-point)
+    (set-company-backend! 'fsharp-mode 'fsharp-ac/company-backend))
   (set-repl-handler! 'fsharp-mode #'run-fsharp)
   (map! :localleader
         :map fsharp-mode-map
         "b" #'fsharp-ac/pop-gotodefn-stack ; Useful for re-tracing your steps
         "e" #'fsharp-eval-region
         "l" #'fsharp-load-buffer-file
-        "q" #'fsharp-ac/stop-process
-        "t" #'fsharp-ac/show-tooltip-at-point))
+        (:unless (featurep! +lsp)
+          "q" #'fsharp-ac/stop-process
+          "t" #'fsharp-ac/show-tooltip-at-point)))