40 lines
1.2 KiB
Racket
40 lines
1.2 KiB
Racket
#lang scheme
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(require web-server/servlet)
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(define (extract-number req)
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(string->number
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(extract-binding/single
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'number
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(request-bindings req))))
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; build-request-page : str str -> response
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(define (build-request-page which-number k-url)
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`(html (head (title "Enter a Number to Add"))
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(body ([bgcolor "white"])
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(form ([action ,k-url] [method "post"])
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"Enter the " ,which-number " number to add: "
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(input ([type "text"] [name "number"] [value ""]))
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(input ([type "submit"] [name "enter"] [value "Enter"]))))))
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(define (get-first req)
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(build-request-page "First" (add-url get-second)))
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(define (get-second req)
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(define fst (extract-number req))
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(build-request-page "Second" (add-url display-sum fst)))
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(define (display-sum req fst)
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(define snd (extract-number req))
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`(html (head (title "Sum"))
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(body ([bgcolor "white"])
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(p "The answer is "
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,(number->string (+ fst snd))))))
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(define-values (start add-url)
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(dispatch-rules
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[("get-second") get-second]
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[("display-sum" (integer-arg)) display-sum]
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[else get-first]))
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(serve/dispatch start)
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