(set-variable): If given a prefix argument, set variable buffer-locally.

Give locality status in prompt.

diff --git a/lisp/simple.el b/lisp/simple.el
index 2b3193ced2df4f9c07831b38ca2f24e9725dc6ed..6b2700f5b7f6b341b6ab7df857398515a19613de 100644 (file)
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3634,7 +3634,7 @@ Each action has the form (FUNCTION . ARGS)."
 (defvar set-variable-value-history nil
   "History of values entered with `set-variable'.")
 
-(defun set-variable (var val)
+(defun set-variable (var val &optional make-local)
   "Set VARIABLE to VALUE.  VALUE is a Lisp object.
 When using this interactively, enter a Lisp object for VALUE.
 If you want VALUE to be a string, you must surround it with doublequotes.
@@ -3644,7 +3644,9 @@ If VARIABLE has a `variable-interactive' property, that is used as if
 it were the arg to `interactive' (which see) to interactively read VALUE.
 
 If VARIABLE has been defined with `defcustom', then the type information
-in the definition is used to check that VALUE is valid."
+in the definition is used to check that VALUE is valid.
+
+With a prefix argument, set VARIABLE to VALUE buffer-locally."
   (interactive
    (let* ((default-var (variable-at-point))
           (var (if (symbolp default-var)
@@ -3653,7 +3655,13 @@ in the definition is used to check that VALUE is valid."
                  (read-variable "Set variable: ")))
                      (minibuffer-help-form '(describe-variable var))
                      (prop (get var 'variable-interactive))
-                     (prompt (format "Set %s to value: " var))
+                     (prompt (format "Set %s%s to value: " var
+                                     (cond ((local-variable-p var)
+                                            " (buffer-local)")
+                                           ((or current-prefix-arg
+                                                (local-variable-if-set-p var))
+                                            " buffer-locally")
+                                           (t " globally"))))
                      (val (if prop
                               ;; Use VAR's `variable-interactive' property
                               ;; as an interactive spec for prompting.
@@ -3663,7 +3671,7 @@ in the definition is used to check that VALUE is valid."
                             (read
                              (read-string prompt nil
                                           'set-variable-value-history)))))
-                (list var val)))
+                (list var val current-prefix-arg)))
 
   (let ((type (get var 'custom-type)))
     (when type
@@ -3673,6 +3681,10 @@ in the definition is used to check that VALUE is valid."
       (unless (widget-apply type :match val)
        (error "Value `%S' does not match type %S of %S"
               val (car type) var))))
+
+  (if make-local
+      (make-local-variable var))
+       
   (set var val)
 
   ;; Force a thorough redisplay for the case that the variable