Make minor mode ARG work as documented

* lisp/emacs-lisp/easy-mmode.el (easy-mmode--arg-docstring):
Clarify when minor modes are switched on/off when called from lisp
(bug#44341).
(define-minor-mode): Make calls from Lisp switch the mode on/off
as documented.

1 files changed, 19 insertions, 9 deletions

diff --git a/lisp/emacs-lisp/easy-mmode.el b/lisp/emacs-lisp/easy-mmode.el
index a707d204f8b..a5a971a6981 100644
--- a/lisp/emacs-lisp/easy-mmode.el
+++ b/lisp/emacs-lisp/easy-mmode.el
@@ -84,10 +84,13 @@ replacing its case-insensitive matches with the literal string in LIGHTER."
 (defconst easy-mmode--arg-docstring
   "
 
-If called interactively, enable %s if ARG is positive, and
-disable it if ARG is zero or negative.  If called from Lisp,
-also enable the mode if ARG is omitted or nil, and toggle it
-if ARG is `toggle'; disable the mode otherwise.
+If called interactively, toggle `%s'.  If the prefix argument is
+positive, enable the mode, and if it is zero or negative, disable
+the mode.
+
+If called from Lisp, toggle the mode if if ARG is `toggle'.
+Enable the mode if ARG is nil, omitted, or is a positive number.
+All other values will disable the mode.
 
 The mode's hook is called both when the mode is enabled and when
 it is disabled.")
@@ -301,13 +304,20 @@ or call the function `%s'."))))
          ,(easy-mmode--mode-docstring doc pretty-name keymap-sym)
 	 ;; Use `toggle' rather than (if ,mode 0 1) so that using
 	 ;; repeat-command still does the toggling correctly.
-	 (interactive (list (or current-prefix-arg 'toggle)))
+	 (interactive (list (if current-prefix-arg
+                                (prefix-numeric-value current-prefix-arg)
+                              'toggle)))
 	 (let ((,last-message (current-message)))
            (,@setter
-            (if (eq arg 'toggle)
-                (not ,getter)
-              ;; A nil argument also means ON now.
-              (> (prefix-numeric-value arg) 0)))
+            (cond ((eq arg 'toggle)
+                   (not ,getter))
+                  ((and (numberp arg)
+                        (> arg 0))
+                   t)
+                  ((eq arg nil)
+                   t)
+                  (t
+                   nil)))
            ,@body
            ;; The on/off hooks are here for backward compatibility only.
            (run-hooks ',hook (if ,getter ',hook-on ',hook-off))