Hi,

Windows 7

Emacs git master/2018.6.24 at least

When I try to toggle hexl-mode, it reports

"defvar: Symbol's value as variable is void: hexl-follow-ascii-mode".

It looks like the definiation of hexl-follow-ascii-mode is incorect.

From the doc of define-minor-mode, it requires INIT-VALUE LIGHTER KEYMAP or at least one keyword argument.

According to the DOC of hexl-follow-ascii-mode, I think the following patch should be proper.

diff --git a/lisp/hexl.el b/lisp/hexl.el
index f37be9d410..6b316dd707 100644
--- a/lisp/hexl.el
+++ b/lisp/hexl.el
@@ -1000,6 +1000,7 @@ hexl-follow-ascii-mode
 When following is enabled, the ASCII character corresponding to the
 element under the point is highlighted.
 The default activation is controlled by `hexl-follow-ascii'."
+  :init-value hexl-follow-ascii
   (if hexl-follow-ascii-mode
       ;; turn it on
       (progn

Best Regards,

Shuguang Sun