From b0a03ed38713a9d04d8e73156eb696517f46a7ae Mon Sep 17 00:00:00 2001
From: 10sr <8.slashes@gmail.com>
Date: Tue, 6 Nov 2018 18:13:26 +0900
Subject: [PATCH] Prevent nested execution

---
 emacs.el | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/emacs.el b/emacs.el
index 87aaa2c..3ef6d81 100644
--- a/emacs.el
+++ b/emacs.el
@@ -1929,6 +1929,9 @@ Delete the text between BEG and END when DELETE is non-nil."
 (defun awk-preview (beg end)
   "Run awk and preview result."
   (interactive "r")
+  (when (and awk-preview--env
+             (awk-preview--env-running-p awk-preview--env))
+    (error "AWK-Preview already running"))
   (let ((e (make-awk-preview--env)))
     (setf (awk-preview--env-point-beg e) beg)
     (setf (awk-preview--env-point-end e) end)