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(list-put vlist ordinal value #!optional (span 1))
Replaces the ordinalth value of vlist with value. If span > 1, replaces ordinal to ordinal+span-1 values starting at ordinal.
(list-put (1 2 3 4 5) 2 0 2) returns (1 0 0 4 5).
Norman Walsh, <ndw@nwalsh.com>
(define (list-put vlist ordinal value #!optional (span 1)) ;; Replace a specific member of a list (let loop ((result vlist) (count span) (k ordinal)) (if (equal? count 0) result (let ((head (list-head result (- k 1))) (tail (list-tail result k))) (loop (append head (list value) tail) (- count 1) (+ k 1))))))
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