68 lines
1.7 KiB
Racket
68 lines
1.7 KiB
Racket
#lang planet dyoo/whalesong
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(require (planet dyoo/whalesong/resource)
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(planet dyoo/whalesong/web-world))
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(define-resource index.html)
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(define (go-forward world dom)
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(add1 world))
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(define (go-backward world dom)
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(max (sub1 world) 0))
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(define (view-top a-view)
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(if (view-up? a-view)
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(view-top (view-up a-view))
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a-view))
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(define (clear-all a-view)
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(define (loop a-view n)
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(define updated-view (update-view-css a-view "background" ""))
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(cond
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[(view-forward? updated-view)
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(loop (view-forward updated-view) (add1 n))]
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[else
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(view-top updated-view)]))
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(loop a-view 0))
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(define (iterate n f x)
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(if (<= n 0)
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x
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(iterate (sub1 n) f (f x))))
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(define (maybe-view-forward a-view)
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(if (view-forward? a-view)
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(view-forward a-view)
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a-view))
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(define (draw world dom)
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(define another-view (update-view-css (iterate world
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maybe-view-forward
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(clear-all dom))
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"background"
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"orange"))
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(update-view-text (view-focus another-view "message")
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(format "Highlighting element ~a\n" world)))
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(define my-initial-view (view-bind
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(view-focus
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(view-bind
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(view-focus (->view index.html)
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"forward")
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"click"
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go-forward)
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"backward")
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"click"
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go-backward))
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(big-bang 0
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(initial-view my-initial-view)
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(to-draw draw)) |