0.9.2.26: refactoring internals of foreign linkage

[sbcl.git] / src / compiler / defconstant.lisp

diff --git a/src/compiler/defconstant.lisp b/src/compiler/defconstant.lisp
index 3356b18..c70e927 100644 (file)
--- a/src/compiler/defconstant.lisp
+++ b/src/compiler/defconstant.lisp
@@ -40,9 +40,16 @@ the usual naming convention (names like *FOO*) for special variables"
        ;; is occasionally more appropriate). -- WHN 2001-12-21
        (unless (eql value
                    (info :variable :constant-value name))
-        (cerror "Go ahead and change the value."
-                "The constant ~S is being redefined."
-                name)))
+        (multiple-value-bind (ignore aborted)
+            (with-simple-restart (abort "Keep the old value.")
+              (cerror "Go ahead and change the value."
+                      'defconstant-uneql
+                      :name name
+                      :old-value (info :variable :constant-value name)
+                      :new-value value))
+          (declare (ignore ignore))
+          (when aborted
+            (return-from sb!c::%defconstant name)))))
       (:global
        ;; (This is OK -- undefined variables are of this kind. So we
        ;; don't warn or error or anything, just fall through.)