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#lang br
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(require racket/sequence)
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(module reader br
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(provide read-syntax)
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(define (read-syntax path ip)
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(strip-context
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#`(module mod numberstring-demo
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#,@(map string->number (regexp-match* #rx"." (string-trim (port->string ip))))))))
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(define (ones->word num)
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(case num
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[(1) "one"][(2) "two"][(3) "three"][(4) "four"][(5) "five"]
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[(6) "six"][(7) "seven"][(8) "eight"][(9) "nine"]))
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(define (tens->word num)
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(case num
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[(2) "twenty"][(3) "thirty"][(4) "forty"][(5) "fifty"]
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[(6) "sixty"][(7) "seventy"][(8) "eighty"][(9) "ninety"]
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[else (number->string num)]))
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(define (two-digit->word num)
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(case num
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[(10) "ten"][(11) "eleven"][(12) "twelve"][(13) "thirteen"][(14) "fourteen"]
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[(15) "fifteen"][(16) "sixteen"][(17) "seventeen"][(18) "eighteen"][(19) "nineteen"]
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[else (string-join (cons (tens->word (quotient num 10))
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(if (positive? (modulo num 10))
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(list (ones->word (modulo num 10)))
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null)) "-")]))
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(define (triple->string triple)
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(match-define (list h t o) triple)
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(string-join
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(append
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(if (positive? h)
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(list (ones->word h) "hundred")
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null)
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(if (positive? t)
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(list (two-digit->word (+ (* 10 t) o)))
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(list (ones->word o)))) " "))
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(define (ones triple) (format "~a" (triple->string triple)))
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(define (thousands triple) (format "~a thousand" (triple->string triple)))
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(define (millions triple) (format "~a million" (triple->string triple)))
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(provide #%datum #%top-interaction (rename-out [mb #%module-begin]))
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(define-macro (mb . DIGITS)
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#'(#%module-begin
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(define digits (list . DIGITS))
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(define padded-digits (append (make-list (- 9 (length digits)) 0) digits))
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(display (string-join (reverse (for/list ([triple (in-slice 3 (reverse padded-digits))]
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[quantifier (list ones thousands millions)]
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#:unless (equal? triple '(0 0 0)))
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(quantifier (reverse triple)))) ", ")))) |