46 lines
990 B
Scheme
46 lines
990 B
Scheme
#lang scheme (require test-engine/scheme-tests)
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(require 2htdp/universe)
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(require htdp/image)
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;; WorldState = Image
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;; graphical constants
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(define mt (empty-scene 100 100))
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;; clack : WorldState Nat Nat String -> Worldstate
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;; add a dot at (x,y) to ws
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(check-expect
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(clack mt 10 20 "button-down")
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(place-image (circle 1 "solid" "red") 10 20 mt))
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(check-expect
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(clack (place-image (circle 1 "solid" "red") 1 2 mt) 3 3 "button-down")
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(place-image (circle 1 "solid" "red") 3 3
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(place-image (circle 1 "solid" "red") 1 2 mt)))
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(define (clack ws x y action)
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(if (string=? "button-down" action)
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(place-image (circle 1 "solid" "red") x y ws)
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ws))
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;; show : WorldState -> WorldState
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;; just reveal the current world state
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(check-expect (show mt) mt)
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(define (show ws)
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ws)
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(test)
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;; run program run
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(define (main x)
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(big-bang (empty-scene 100 100)
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(on-draw show)
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(record? x)
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(on-mouse clack)))
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(main false)
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