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Paste # 64376
2016-07-22 16:53:36

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  1. #lang racket
  2.  
  3. ; uncomment this
  4. ; (require racket/gui)
  5.  
  6. (define f (new frame% [label "foo"]))
  7. (define p (new panel% [parent f]))
  8.  
  9. (define (do-canvas str)
  10.   (new canvas%
  11.        [min-width 50]
  12.        [min-height 50]
  13.        [parent p]
  14.        [style '(transparent)]
  15.        [paint-callback
  16.         (λ (cv dc)
  17.           (send dc draw-text str 25 25))]))
  18.  
  19. (do-canvas "Hello World")
  20. (do-canvas "Goodbye World")
  21. (do-canvas "Potatoes")
  22.  
  23. (send f show #t)

=>

frame%: undefined;

 cannot reference an identifier before its definition

  in module: 'm

panel%: undefined;

 cannot reference an identifier before its definition

  in module: 'm

canvas%: undefined;

 cannot reference an identifier before its definition

  in module: 'm

canvas%: undefined;

 cannot reference an identifier before its definition

  in module: 'm

canvas%: undefined;

 cannot reference an identifier before its definition

  in module: 'm

f: undefined;

 cannot reference an identifier before its definition

  in module: 'm