(set-variable): Check VALUE against type info if available.

Don't evaluate VALUE.
Use a separate history list for the values.

1 files changed, 45 insertions, 18 deletions

diff --git a/lisp/simple.el b/lisp/simple.el
index 92da208797a..2d8cffe9c52 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3006,6 +3006,49 @@ Each action has the form (FUNCTION . ARGS)."
   (compose-mail to subject other-headers continue
                 'switch-to-buffer-other-frame yank-action send-actions))
 
+(defvar set-variable-value-history nil
+  "History of values entered with `set-variable'.")
+
+(defun set-variable (var val)
+  "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.
+VALUE is used literally, not evaluated.
+
+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."
+  (interactive (let* ((var (read-variable "Set variable: "))
+                      (minibuffer-help-form '(describe-variable var))
+                      (prop (get var 'variable-interactive))
+                      (prompt (format "Set %s to value: " var))
+                      (val (if prop
+                               ;; Use VAR's `variable-interactive' property
+                               ;; as an interactive spec for prompting.
+                               (call-interactively `(lambda (arg)
+                                                      (interactive ,prop)
+                                                      arg))
+                             (read
+                              (read-string prompt nil
+                                           'set-variable-value-history)))))
+                 (list var val)))
+
+  (let ((type (get var 'custom-type))
+        widget)
+    (when type
+      ;; Match with custom type.
+      (require 'wid-edit)
+      (unless (listp type)
+        (setq widget (list type)))
+      (setq type (widget-convert type))
+      (unless (widget-apply type :match val)
+        (error "Value `%S' does not match type %S of %S" 
+               val (car type) var))))
+  (set var val))
+
+
 (defun set-variable (var val)
   "Set VARIABLE to VALUE.  VALUE is a Lisp object.
 When using this interactively, supply a Lisp expression for VALUE.
@@ -3022,24 +3065,7 @@ it were the arg to `interactive' (which see) to interactively read the value."
                   "Set variable: ")
                 obarray 'user-variable-p t))
           (var (if (equal val "") v (intern val)))
-          (minibuffer-help-form
-           '(funcall myhelp))
-          (myhelp
-           (function
-            (lambda ()
-              (with-output-to-temp-buffer "*Help*"
-                (prin1 var)
-                (princ "\nDocumentation:\n")
-                (princ (substring (documentation-property var 'variable-documentation)
-                                  1))
-                (if (boundp var)
-                    (let ((print-length 20))
-                      (princ "\n\nCurrent value: ")
-                      (prin1 (symbol-value var))))
-                (save-excursion
-                  (set-buffer standard-output)
-                  (help-mode))
-                nil)))))
+)
      (list var
            (let ((prop (get var 'variable-interactive)))
              (if prop
@@ -3050,6 +3076,7 @@ it were the arg to `interactive' (which see) to interactively read the value."
                                            'arg))
                (eval-minibuffer (format "Set %s to value: " var)))))))
   (set var val))
+
 
 ;; Define the major mode for lists of completions.