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eniehack/run-length.scm

Created July 13, 2022 16:42
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run-length.scm
(define (run-length s)
(letrec ((run-length-h (lambda (s vec count prev-char)
(if (null? s)
(vector-append vec (vector `(,prev-char ,count)))
(let ((c (car s)))
(if (char=? prev-char c)
(run-length-h (cdr s) vec (+ count 1) prev-char)
(if (char=? prev-char #\null)
(run-length-h (cdr s) vec 1 c)
(run-length-h (cdr s) (vector-append vec (vector `(,prev-char ,count))) 1 c))))))))
(run-length-h s '#() 0 #\null)))
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