From ac31e6edc27e252c984ab4be1df205b09866876f Mon Sep 17 00:00:00 2001
From: Sergey Vinokurov <serg.foo@gmail.com>
Date: Sun, 17 May 2015 23:22:05 +0300
Subject: [PATCH] don't silently ignore case when ghc process is already
 running in ghc-with-process

---
 elisp/ghc-process.el | 45 +++++++++++++++++++++++---------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/elisp/ghc-process.el b/elisp/ghc-process.el
index b44416e..0519549 100644
--- a/elisp/ghc-process.el
+++ b/elisp/ghc-process.el
@@ -18,7 +18,8 @@
 (defvar-local ghc-process-original-buffer nil)
 (defvar-local ghc-process-original-file nil)
 (defvar-local ghc-process-callback nil)
-(defvar-local ghc-process-hook nil)
+(defvar-local ghc-process-hook nil
+  "Hook that will be called upon successfull completion of ghc-mod command.")
 
 (defvar ghc-command "ghc-mod")
 
@@ -30,26 +31,28 @@
 (defun ghc-with-process (cmd callback &optional hook1 hook2)
   (unless ghc-process-process-name
     (setq ghc-process-process-name (ghc-get-project-root)))
-  (when (and ghc-process-process-name (not ghc-process-running))
-    (setq ghc-process-running t)
-    (if hook1 (funcall hook1))
-    (let* ((cbuf (current-buffer))
-	   (name ghc-process-process-name)
-	   (buf (get-buffer-create (concat " ghc-mod:" name)))
-	   (file (buffer-file-name))
-	   (cpro (get-process name)))
-      (ghc-with-current-buffer buf
-        (setq ghc-process-original-buffer cbuf)
-	(setq ghc-process-original-file file)
-	(setq ghc-process-callback callback)
-	(setq ghc-process-hook hook2)
-	(erase-buffer)
-	(let ((pro (ghc-get-process cpro name buf)))
-	  (process-send-string pro cmd)
-	  (when ghc-debug
-	    (ghc-with-debug-buffer
-	     (insert (format "%% %s" cmd))))
-	  pro)))))
+  (if ghc-process-running
+    (error "ghc process already running")
+    (progn
+      (when ghc-process-running t)
+      (if hook1 (funcall hook1))
+      (let* ((cbuf (current-buffer))
+             (name ghc-process-process-name)
+             (buf (get-buffer-create (concat " ghc-mod:" name)))
+             (file (buffer-file-name))
+             (cpro (get-process name)))
+        (ghc-with-current-buffer buf
+          (setq ghc-process-original-buffer cbuf)
+          (setq ghc-process-original-file file)
+          (setq ghc-process-callback callback)
+          (setq ghc-process-hook hook2)
+          (erase-buffer)
+          (let ((pro (ghc-get-process cpro name buf)))
+            (process-send-string pro cmd)
+            (when ghc-debug
+              (ghc-with-debug-buffer
+               (insert (format "%% %s" cmd))))
+            pro))))))
 
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