Setup lsp server election process for cpp

lisp/fg42/editor.el

@@ -21,15 +21,16 @@
 ;;
 ;;; Commentary:
 ;;; Code:
+
 (eval-when-compile
   (require 'fpkg)
   ;; Language support
-)
+  (require 'fg42/autocomplete)
+  (require 'fg42/langs/cpp))
+
 (require 'server)
 (require 'fg42/modeline)
 
-(require 'fg42/autocomplete)
-(require 'fg42/langs/cpp)
 
 ;; (require 'fg42/utils)
 ;; (require 'fg42/modeline)
@@ -93,6 +94,7 @@ external dependencies."
     "Use ripgrep with projectile"
     :after projectile)
 
+
   (use! helpful
     "Helpful is an alternative to the built-in Emacs help that provides much more
 contextual information."

lisp/fg42/langs/cpp.el

@@ -32,9 +32,7 @@
    "--pch-storage=memory"
    "--background-index"
    "--cross-file-rename"
-   "--completion-style=detailed"
-   "--malloc-trim"
-   )
+   "--completion-style=detailed")
   "Arguments to pass to clangd.")
 
 (use! cmake-ts-mode
@@ -50,13 +48,29 @@
 https://github.com/ninja-build/ninja/blob/master/misc/ninja-mode.el")
 
 
+(defun fg42/c_cpp_ls (_)
+  "Return the proper lang server fo C/C++.
+By default it will return `clangd' or `ccls' depends on what you have
+installed.  If you set `CPP_LS' env variable, then the value of that
+var will be used instead.  You can use `add-advice' to change the
+return value of this function as well."
+    (let ((ls (getenv "CPP_LS")))
+      (if (null ls)
+          (eglot-alternatives `(("clangd" ,@fg42/clangd-args) ("ccls")))
+        (split-string ls " "))))
+
+
 (defun fg42/c-ts-mode-setup ()
   "A hook handler to setup cpp related configurations."
   (message "[FG42][C/C++]: Make sure to setup clangd to fit your needs. For more info: https://clangd.llvm.org/config")
   (setq-local company-backends
               '((company-capf :with company-yasnippet) :separate
                 (company-keywords company-dabbrev company-ispell) :separate
-                company-files)))
+                company-files))
+  ;; We set eglot's autoload command to `eglot-ensure'
+  (eglot-ensure)
+  (add-to-list 'eglot-server-programs
+               `(c++-ts-mode . ,#'fg42/c_cpp_ls)))
 
 
 (use! c-ts-mode
@@ -67,15 +81,7 @@ https://github.com/ninja-build/ninja/blob/master/misc/ninja-mode.el")
   (add-to-list 'major-mode-remap-alist '(c++-mode . c++-ts-mode))
   (add-to-list 'major-mode-remap-alist '(c-or-c++-mode . c-or-c++-ts-mode))
 
-  :config
-  ;; Set the default lang server for C/C++ to clangd
-  (with-eval-after-load 'eglot
-    (add-to-list
-     'eglot-server-programs
-     `(c-mode c++-mode c-ts-mode c++-ts-mode . ("clangd" ,@fg42/clangd-args))))
-
   :hook
-  (c++-ts-mode . eglot-ensure)
   (c++-ts-mode . company-mode)
   (c++-ts-mode . fg42/c-ts-mode-setup)
   (c++-ts-mode . flyspell-prog-mode))