Remove ruby-end-mode and use smartparens instead

ruby-end-mode does not always behave correctly. An example for that is
if statements, which don't have an end statement if they are written on
one line. Also, it feels dirty to use a Ruby package to implement Elixir
syntax behaviour.
Smartparens has functionality to define pairs for certain major modes.
This adds smartparens pairs for the "do" keyword and the arrow (->)
operator, so that the "end" keyword is automatically inserted and
properly indented on enter.

layers/+lang/elixir/packages-config.el

@@ -102,6 +102,25 @@
   (spacemacs|add-company-hook elixir-mode)
   (spacemacs|add-company-hook alchemist-iex-mode))
 
+(defun elixir-do-end-close-action (id action context)
+  (when (eq action 'insert)
+    (newline-and-indent)
+    (forward-line -1)
+    (indent-according-to-mode)))
+
+(defun elixir/post-init-smartparens ()
+  (sp-with-modes '(elixir-mode)
+    (sp-local-pair "->" "end"
+                   :when '(("RET"))
+                   :post-handlers '(:add elixir-do-end-close-action)
+                   :actions '(insert)))
+
+  (sp-with-modes '(elixir-mode)
+    (sp-local-pair "do" "end"
+                   :when '(("SPC" "RET"))
+                   :post-handlers '(:add elixir-do-end-close-action)
+                   :actions '(insert))))
+
 (defun elixir/init-elixir-mode ()
   (use-package elixir-mode
     :defer t))
@@ -110,27 +129,3 @@
   (spacemacs|use-package-add-hook popwin
     :post-config
     (push '("*mix*" :tail t :noselect t) popwin:special-display-config)))
-
-(defun elixir/init-ruby-end ()
-  (use-package ruby-end
-    :defer t
-    :init
-    (progn
-      (defun spacemacs//ruby-end ()
-        (set (make-variable-buffer-local 'ruby-end-expand-keywords-before-re)
-             "\\(?:^\\|\\s-+\\)\\(?:do\\)")
-        (set (make-variable-buffer-local 'ruby-end-check-statement-modifiers)
-             nil)
-        (ruby-end-mode +1))
-      (add-hook 'elixir-mode-hook 'spacemacs//ruby-end)
-      ;; hack to remove the autoloaded `add-hook' in `ruby-end'
-      ;; since they are inserted as an autoload, they have to be removed both
-      ;; before and after loading
-      (remove-hook 'ruby-mode-hook 'ruby-end-mode)
-      (remove-hook 'enh-ruby-mode-hook 'ruby-end-mode))
-    :config
-    (progn
-      (spacemacs|hide-lighter ruby-end-mode)
-      ;; see comment in `:init' block
-      (remove-hook 'ruby-mode-hook 'ruby-end-mode)
-      (remove-hook 'enh-ruby-mode-hook 'ruby-end-mode))))

layers/+lang/elixir/packages.el

@@ -15,5 +15,5 @@
     company
     elixir-mode
     popwin
-    ruby-end
+    smartparens
     ))