Made attribute class layered

[clinton/lisp-on-lines.git] / src / standard-descriptions / clos.lisp

diff --git a/src/standard-descriptions/clos.lisp b/src/standard-descriptions/clos.lisp
index ec80d86..2824c2e 100644 (file)
--- a/src/standard-descriptions/clos.lisp
+++ b/src/standard-descriptions/clos.lisp
@@ -8,13 +8,29 @@
  ((slot-name :initarg :slot-name :accessor attribute-slot-name)))
 
 (define-layered-method attribute-value (object (attribute slot-definition-attribute))
-  (slot-value object (attribute-slot-name attribute)))
+  (if (slot-boundp object (attribute-slot-name attribute))
+                      
+      (slot-value object (attribute-slot-name attribute))
+      (gensym "UNBOUND-SLOT-")))
+
+(defmacro define-description-for-class (class-name &optional (name (intern (format nil "DESCRIPTION-FOR-~A" class-name))))
+  `(progn 
+     (define-description ,name (standard-object)
+       ,(loop :for slot in (class-slots (find-class class-name))
+         :collect `(,(slot-definition-name slot) 
+                   :attribute-class slot-definition-attribute
+                   :slot-name ,(slot-definition-name slot)
+                   :label ,(slot-definition-name slot)))
+       (:mixinp t))
+     (unless (ignore-errors (find-description ',class-name))
+       (define-description ,class-name (,name) ()))))
+    
                       
                      
 (define-layered-method description-of ((object standard-object))
- (find-description 'standard-object))
-
-
+  (or (ignore-errors (find-description (class-name (class-of object))))
+      (find-description 'standard-object)))
+