0.8.19.25:

[sbcl.git] / src / pcl / defcombin.lisp

diff --git a/src/pcl/defcombin.lisp b/src/pcl/defcombin.lisp
index 13781e5..060f4a0 100644 (file)
--- a/src/pcl/defcombin.lisp
+++ b/src/pcl/defcombin.lisp
@@ -25,10 +25,13 @@
 \f
 (defmacro define-method-combination (&whole form &rest args)
   (declare (ignore args))
-  (if (and (cddr form)
-          (listp (caddr form)))
-      (expand-long-defcombin form)
-      (expand-short-defcombin form)))
+  `(progn
+     (with-single-package-locked-error
+        (:symbol ',(second form) "defining ~A as a method combination"))
+     ,(if (and (cddr form)
+              (listp (caddr form)))
+         (expand-long-defcombin form)
+         (expand-short-defcombin form))))
 \f
 ;;;; standard method combination
 
@@ -298,6 +301,12 @@
 
 ;; parse-method-group-specifiers parse the method-group-specifiers
 
+(define-condition long-method-combination-error 
+    (reference-condition simple-error)
+  ()
+  (:default-initargs 
+      :references (list '(:ansi-cl :macro define-method-combination))))
+
 (defun wrap-method-group-specifier-bindings
        (method-group-specifiers declarations real-body)
   (let (names
@@ -316,16 +325,19 @@
                    (if (and (equal ,specializer-cache .specializers.)
                             (not (null .specializers.)))
                        (return-from .long-method-combination-function.
-                         '(error "More than one method of type ~S ~
-                                     with the same specializers."
-                                  ',name))
+                         '(error 'long-method-combination-error
+                           :format-control "More than one method of type ~S ~
+                                            with the same specializers."
+                           :format-arguments (list ',name)))
                        (setq ,specializer-cache .specializers.))
                    (push .method. ,name))
                  cond-clauses)
            (when required
              (push `(when (null ,name)
                         (return-from .long-method-combination-function.
-                          '(error "No ~S methods." ',name)))
+                          '(error 'long-method-combination-error
+                            :format-control "No ~S methods." 
+                            :format-arguments (list ',name))))
                      required-checks))
            (loop (unless (and (constantp order)
                               (neq order (setq order (eval order))))