Changeset 12578

Timestamp:

03/28/10 21:41:27 (13 years ago)

Author:

astalla

Message:

Selected built-in classes can now be subclassed. Only SEQUENCE is allowed as of this revision.
This makes sequences user-extensible again.

File:

• trunk/abcl/src/org/armedbear/lisp/clos.lisp (modified) (2 diffs)

trunk/abcl/src/org/armedbear/lisp/clos.lisp

@@ -579 +579 @@
   (getf canonical-slot :name))
 
+(defvar *extensible-built-in-classes* (list (find-class 'sequence)))
+
 (defun ensure-class (name &rest all-keys &key metaclass &allow-other-keys)
   ;; Check for duplicate slots.
@@ -603 +605 @@
   (let ((direct-superclasses (getf all-keys :direct-superclasses)))
     (dolist (class direct-superclasses)
-      (when (typep class 'built-in-class)
+      (when (and (typep class 'built-in-class)
+     (not (member class *extensible-built-in-classes*)))
         (error "Attempt to define a subclass of a built-in-class: ~S" class))))
   (let ((old-class (find-class name nil)))