Simplify the folder structure

languages/erlang.el

@@ -0,0 +1,88 @@
+(cl-defun erlang/emacs-path (erlang-version)
+  (car (split-string
+        (shell-command-to-string
+         (format "find $HOME/.asdf/installs/erlang/%s/ -name erlang.el"
+                 erlang-version)) "erlang.el")))
+
+(cl-defun erlang/erlang-path (erlang-version)
+  (format "$HOME/.asdf/installs/erlang/%s/" erlang-version))
+
+(defun erlang/erlang-plist (erlang-version)
+  "Create property list for ERLANG-VERSION."
+  (list :version erlang-version
+        :erlang-path (erlang/erlang-path erlang-version)
+        :emacs-path (erlang/emacs-path erlang-version)))
+
+(cl-defun erlang/installed-erlangs ()
+  (split-string
+   (shell-command-to-string
+    (format "asdf list erlang"))))
+
+(cl-defun erlang/available-versions--plist ()
+  (mapcar 'erlang/erlang-plist (erlang/installed-erlangs)))
+
+(setq erlang/available-versions (erlang/available-versions--plist))
+
+(cl-defun erlang/currently-in-use ()
+  (car (split-string (shell-command-to-string "asdf current erlang"))))
+
+(cl-defun erlang/current-version--plistp (erlang-plist)
+  (equal (plist-get erlang-plist :version) (erlang/currently-in-use)))
+
+(cl-defun erlang/current-plist ()
+  (seq-find 'erlang/current-version--plistp erlang/available-versions))
+
+;; Flycheck checker for Erlang
+(flycheck-define-checker erlang-otp
+  "An Erlang syntax checker using the Erlang interpreter."
+  :command ("erlc" "-o" temporary-directory "-Wall"
+            "-I" "../include" "-I" "../../include"
+            "-I" "../../../include" source)
+  :error-patterns
+  ((warning line-start (file-name) ":" line ": Warning:" (message) line-end)
+   (error line-start (file-name) ":" line ": " (message) line-end))
+  :modes (my-erlang-mode))
+
+(defun erlang/activate-erlang-mode ()
+  "All things for all Erlang, including header files."
+  (when (featurep 'erlang-start) (unload-feature 'erlang-start))
+
+  (setq erlang/current-erlang (erlang/current-plist))
+
+  (add-to-list (make-local-variable 'load-path)
+               (plist-get erlang/current-erlang :emacs-path))
+
+  (add-to-list (make-local-variable 'exec-path)
+               (format "%slib/tools-3.1/emacs"
+                       (plist-get erlang/current-erlang :erlang-path)))
+
+  (setq-local erlang-man-root-dir
+              (format "%sman"
+                      (plist-get erlang/current-erlang :erlang-path)))
+
+  (require 'erlang-start)
+
+  ;; Set specific ctags command
+  (setq-local
+   ctags/refresh-command
+   (format
+    "ctags -e -R --languages=erlang -f %sTAGS %s. %slib/stdlib-* %slib/kernel-*"
+    (projectile-project-root) (projectile-project-root)
+    (plist-get erlang/current-erlang :erlang-path)
+    (plist-get erlang/current-erlang :erlang-path)))
+
+  ;; Company list override
+  (add-to-list (make-local-variable 'company-backends)
+               '(company-etags company-yasnippet)))
+
+(add-hook 'erlang-mode-hook 'erlang/activate-erlang-mode)
+
+(define-derived-mode my-erlang-mode erlang-mode "My Erlang mode"
+  "A mode for Erlang things"
+
+  (activate-erlang-mode)
+  ;; Enable flycheck
+  (flycheck-select-checker 'erlang-otp)
+
+  ;; Automatically update tags on save
+  (ctags/update-this-mode-on-save 'erlang-mode))