44 lines
1.4 KiB
Scheme
44 lines
1.4 KiB
Scheme
(require "../simple.ss")
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(require (rename (lib "mred.ss" "mred") horizontal-panel% horizontal-panel%))
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; just change this to change the range of the binary/decimal converter
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(define SIZE 10)
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(define (bool-lst->num bool-lst)
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(let loop ([lst bool-lst] [sum 0] [pow 0])
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(if (empty? lst)
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sum
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(loop (cdr lst)
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(+ sum
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(if (car lst)
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(expt 2 pow)
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0))
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(add1 pow)))))
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(define (place-num->bool loc num)
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(if (= 0 loc)
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(odd? num)
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(place-num->bool (sub1 loc) (quotient num 2))))
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(current-widget-parent (new ft-frame% (label "Binary<-->Decimal")))
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(define-values-rec
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[sld (mode value-b ft-slider%
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(stretchable-width #t)
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(min-value 0)
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(max-value (sub1 (expt 2 SIZE)))
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(value-set (changes
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(bool-lst->num
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boxes))))]
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[boxes (parameterize ([current-widget-parent
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(mode widget horizontal-panel%)])
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(build-list SIZE ; build-list is right associative.
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(lambda (i)
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(mode value-b ft-check-box%
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(label (number->string (expt 2 i)))
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(value-set
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(changes (place-num->bool i sld)))))))])
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(send (current-widget-parent) show #t) |