35 lines
989 B
Plaintext
35 lines
989 B
Plaintext
{ (define LIBNAME "Arrows GUI")
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(include "head.tinc") }
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<p>The teachpack <code>arrow-gui.ss</code> implements three functions:
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<menu>
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<li> <code>{(idx control)} : -> symbol</code> <br>
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to read out the current state of the message field
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<li> <code>{(idx view)} : (union string symbol) -> true</code> <br>
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to display its argument in the message field
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<li> <code>modelT = (button% event% -> true)</code> <br>
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<code>{(idx connect)} : modelT modelT modelT modelT -> true</code> <br>
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to connect four controllers with the four directions in the arrow window
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</menu>
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<p>Example:
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<pre>
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> (define (make-model dir)
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(lambda (b e)
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(begin
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(view dir)
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(printf "~a ~n" (control)))))
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> (connect
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(make-model "left")
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(make-model "right")
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(make-model "up")
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(make-model "down"))
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</pre>
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Now click on the four arrows. The message field will contain the current
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direction, the print-out the prior contents of the message field.
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{(include "foot.tinc")}
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