diff options
Diffstat (limited to 'mew.scm')
| -rw-r--r-- | mew.scm | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/mew.scm b/mew.scm index 695568b..22a8752 100644 --- a/mew.scm +++ b/mew.scm @@ -17,7 +17,8 @@ odometer one-of op op* per prn proj puts rand range rep - sample scan scan-right sing? search seq set set-at shuffle str slurp + sample scan scan-right sing? search seq set set-at + shuffle shuffle! str slurp tally-accumulator tbl time while uniq-accumulator unlist until @@ -404,7 +405,7 @@ ((n) (pseudo-random-integer n)) ((n m) (+ n (pseudo-random-integer (- m n)))))) - (define (shuffle v) + (define (shuffle! v) (let loop ((i (- (vector-length v) 1))) (when (positive? i) (let* ((j (rand (+ i 1))) @@ -415,6 +416,16 @@ (loop (dec i))))) v) + (define (shuffle v) + (let ((l (vector-length v))) + (do ((res (make-vector l)) + (i 0 (+ i 1))) + ((= i l) res) + (let ((j (rand (+ i 1)))) + (unless (= j i) + (vector-set! res i (vector-ref res j))) + (vector-set! res j (vector-ref v i)))))) + (define (sample o) (if (hash-table? o) (esc ret |