(defparameter *handlers* nil)

(defun handler (x)
  (let ((what (cdr (assoc (intern (string-upcase x)) *handlers* ))))
    (if what
	(funcall what)
      (error "no handler for ~a" x))))
    
(defun register (withThis this)
  (let ((maker (intern  (string-upcase (format nil "make-~a" withThis)))))
    (push (cons this maker) *handlers*)))

(register 'tagwidth 'width)

(defmethod linesForAt ((x tagwidth) words this line)
  (if words
    (setf (graph-w this) (parse-integer (first words)))
    (error "~a) expected 1 argument" line)))