;; Inputs is of the form
;; k => name provided by user for input
;; v => the code generated to make an instance
;; ex: (:scale pony 0 10 1) creates an entry
       ;; where pony=>(make-instance 'scale ...)
(defparameter *inputs* (make-hash-table))
;; The parameters passed to the action function.
(defparameter *params* nil)
;; Resets the model
(defun reset-inputs ()
  (setf *inputs* (make-hash-table))
  (setf *params* '()))
;; Converts a keyworded form to the 
;;appropriate LTK make-instance.
;; Side-effect: Adds the instance to *inputs*
(defun convert-to-instance (keyword)
  (let ((key  (first  keyword)) ; eg: :scale
        (name (second keyword)) ; 
        (vals (cddr   keyword)) ; all additional parameters
        (special (eql 'special (first (last keyword))))
        tmp)
    (cond
      ((equal key :scale)
       (progn
         (setf tmp 
	       `(make-instance 'scale
			       :master main-label
			       :label ,(format nil "~A" name)
			       :from ,(first vals)
			       :to ,(second vals)
			       :digits 5
			       :resolution ,(or (third vals) 1)
			       :troughcolor ,(if special :red :black)
			       :orientation 'horizontal))
         (setf (gethash name *inputs*) tmp))))
    tmp))
(defmacro defmodel (name inputs model importance &body action)
  (reset-inputs)
  (let (
        letz   ; all LTK forms
        packer 
	;;generated from letz, a sequence of (pack NAME)
        ui-name
        model-name
        function-name
        function-parameters
        importance-name
        )
    ; Generates two symbols: NAME-MODEL and NAME-PROCESSOR
    (setf model-name (intern (format nil "~A-MODEL" 
				     name)))
    (setf function-name (intern (format nil "~A-PROCESSOR" 
					name)))
    (setf ui-name (intern (format nil "~A-UI" name)))
    (setf importance-name (intern (format nil "~A-IMPORTANCE" 
					  name)))