26 lines
938 B
Scheme
26 lines
938 B
Scheme
(require (lib "xml.ss" "xml")
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(lib "unit.ss")
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(lib "servlet-sig.ss" "web-server")
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"helper-sig.ss")
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(unit
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(import servlet^)
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(export my-servlet-helpers^)
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; get-number : string -> number
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; to prompt the user for a number
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(define (get-number which-number)
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(let ask ([error-message null])
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(let* ([n-str
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(extract-binding/single
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'n
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(request-bindings
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(send/suspend
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(let ([prompt (string-append "Enter " which-number ": ")])
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(build-suspender
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(list prompt)
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`(,@error-message
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(p ,prompt (input ([type "text"] [name "n"])))
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(input ([type "submit"] [value "Okay"]))))))))]
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[n (string->number n-str)])
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(or n (ask `((p (font ([color "red"]) ,n-str) " is not a number. Please enter a number.")))))))) |