move lisp programs to directory

lisp/ulos.lsp

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+;
+; ULOS simple object system
+; see http://forum.ulisp.com/t/a-simple-object-system-for-ulisp/622
+;
+
+; Define an object
+(defun object (&optional parent slots)
+  (let ((obj (when parent (list (cons 'parent parent)))))
+    (loop
+     (when (null slots) (return obj))
+     (push (cons (first slots) (second slots)) obj)
+     (setq slots (cddr slots)))))
+
+; Get the value of a slot in an object or its parents
+(defun value (obj slot)
+  (when (symbolp obj) (setq obj (eval obj)))
+  (let ((pair (assoc slot obj)))
+    (if pair (cdr pair)
+           (let ((p (cdr (assoc 'parent obj))))
+             (and p (value p slot))))))
+
+; Update a slot in an object
+(defun update (obj slot value)
+  (when (symbolp obj) (setq obj (eval obj)))
+  (let ((pair (assoc slot obj)))
+    (when pair (setf (cdr pair) value))))