From b6b40bb4abad3b4ca704f50c108781db81110573 Mon Sep 17 00:00:00 2001
From: Soonho Kong <soonhok@cs.cmu.edu>
Date: Thu, 7 Aug 2014 11:38:20 -0700
Subject: [PATCH] feat(emacs): use optional package when required

---
 src/emacs/lean-flycheck.el | 2 ++
 src/emacs/lean-mode.el     | 9 ++++-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/emacs/lean-flycheck.el b/src/emacs/lean-flycheck.el
index 8fc4a2ced..591e7a8d7 100644
--- a/src/emacs/lean-flycheck.el
+++ b/src/emacs/lean-flycheck.el
@@ -4,6 +4,8 @@
 ;; Author: Soonho Kong
 ;;
 
+(require 'flycheck)
+
 (setq-local lean-lmake-name "lmake")
 (setq-local lean-lmake-options "--flycheck")
 (eval
diff --git a/src/emacs/lean-mode.el b/src/emacs/lean-mode.el
index ca584cf5c..f70b9d07e 100644
--- a/src/emacs/lean-mode.el
+++ b/src/emacs/lean-mode.el
@@ -8,9 +8,6 @@
 (require 'generic-x)
 (require 'compile)
 (require 'flymake)
-(require 'flycheck)
-(require 'fill-column-indicator)
-(require 'whitespace-cleanup-mode)
 (require 'lean-util)
 (require 'lean-settings)
 (require 'lean-flycheck)
@@ -84,10 +81,12 @@
       (when (and lean-rule-column
                  lean-show-rule-column-method)
         (cl-case lean-show-rule-column-method
-          ('vline (setq fci-rule-column lean-rule-column)
+          ('vline (require 'fill-column-indicator)
+                  (setq fci-rule-column lean-rule-column)
                   (add-hook 'lean-mode-hook 'fci-mode))))
       (if lean-delete-trailing-whitespace
-          (add-hook 'lean-mode-hook 'whitespace-cleanup-mode)
+          (progn (require 'whitespace-cleanup-mode)
+                 (add-hook 'lean-mode-hook 'whitespace-cleanup-mode))
         (remove-hook 'lean-mode-hook 'whitespace-cleanup-mode))
       ))
   "A mode for Lean files"          ;; doc string for this mode