; http://lispy.wordpress.com/2007/07/09/closures-hash-tables-as-much-oop-as-youll-ever-need/
; for a more complete oo-in-lisp, see
; http://lib.store.yahoo.net/lib/paulgraham/acl2.lisp
; (search in that file for "parents"

(defun create-obi ()
  (let ((h (make-hash-table)))
    (lambda (command field &optional value)
      (case command
	(get (gethash field h))
	(set (setf (gethash field h) value))
	(run (apply (gethash field h) value))))))

(defun ~ (obi field)
  (funcall obi 'get field))

(defun ~> (obi field value)
  (funcall obi 'set field value))

(defun ~! (obi field arguments)
  (funcall obi 'run field arguments))

#|
; SLIME: The Superior Lisp Interaction Mode for Emacs
CL-USER> (setf f (create-obi))
#<COMPILED-CLOSURE CREATE-OBI-1>
CL-USER> (~> f 'color 'red)
RED
CL-USER> (~> f 'shape 'square)
SQUARE
CL-USER> (~ f 'color)
RED
T
CL-USER> (~ f 'shape)
SQUARE
T
CL-USER> (~> f 'add #'+)
#<SYSTEM-FUNCTION +>
CL-USER> (~! f 'add '(1 2 3 4 5 6 7))
28

|#