swapping-tab-panel.rkt

#lang racket/gui
(require framework)

(define swapping-tab-panel%
  (class tab-panel%
    (inherit get-selection set-selection set)
    (super-new [callback
		(lambda (b e)
		  (when (eq? 'tab-panel (send e get-event-type))
		    (send swapper-panel active-child
			  (vector-ref children-vec (get-selection)))))])

    (define children-vec '())
    (define swapper-panel
      (new (panel:single-mixin panel%)
	   [parent this]))

    (define/public (get-container) swapper-panel)
    (define/public (set-children children)
      (for ([c children]) (send c reparent swapper-panel))
      (set (map (lambda (c) (send c get-label)) children))
      (set-selection 0)
      (send swapper-panel active-child (first children))
      (set! children-vec (list->vector children)))))