Changeset 2868

Timestamp:

2015-06-21T11:25:07-07:00 (10 years ago)

Author:

Marek Rychlik

Message:

* empty log message *

File:

• branches/f4grobner/ring.lisp (modified) (1 diff)

branches/f4grobner/ring.lisp

@@ -199 +199 @@
 (defgeneric append-item (self item))
 
+;; Source: http://stackoverflow.com/questions/11067899/is-there-a-generic-method-for-cloning-clos-objects
+(defgeneric copy-instance (object &rest initargs &key &allow-other-keys)
+  (:documentation "Makes and returns a shallow copy of OBJECT.
+
+  An uninitialized object of the same class as OBJECT is allocated by
+  calling ALLOCATE-INSTANCE.  For all slots returned by
+  CLASS-SLOTS, the returned object has the
+  same slot values and slot-unbound status as OBJECT.
+
+  REINITIALIZE-INSTANCE is called to update the copy with INITARGS.")
+  (:method ((object standard-object) &rest initargs &key &allow-other-keys)
+    (let* ((class (class-of object))
+           (copy (allocate-instance class)))
+      (dolist (slot-name (mapcar #'sb-mop:slot-definition-name (sb-mop:class-slots class)))
+    (when (slot-boundp object slot-name)
+      (setf (slot-value copy slot-name)
+        (slot-value object slot-name))))
+      (apply #'reinitialize-instance copy initargs))))