23 lines
759 B
Racket
23 lines
759 B
Racket
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#lang racket
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(define (wrap words width)
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(define (maybe-cons xs xss)
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(if (empty? xs) xss (cons xs xss)))
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(match/values
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(for/fold ([lines '()] [line '()] [left width]) ([w words])
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(define n (string-length w))
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(cond
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[(> n width) ; word longer than line => line on its own
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(values (cons (list w) (maybe-cons line lines)) '() width)]
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[(> n left) ; not enough space left => new line
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(values (cons line lines) (list w) (- width n 1))]
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[else
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(values lines (cons w line) (- left n 1))]))
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[(lines line _)
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(apply string-append
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(for/list ([line (reverse (cons line lines))])
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(string-join line #:after-last "\n")))]))
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;;; Usage:
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(wrap (string-split text) 70)
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