scsh-conservatory
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scsh-0.5
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Added a few bits.

This commit is contained in:
shivers 1997-02-19 23:29:41 +00:00
parent bad528299e
commit 630f678236
1 changed files with 28 additions and 0 deletions
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28
scsh/utilities.scm
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@ -170,3 +170,31 @@
(let ((f (round x))) (let ((f (round x)))
(if (inexact? f) (inexact->exact f) f))) (if (inexact? f) (inexact->exact f) f)))
;;; Copy string SOURCE into TARGET[start,...]
(define (string-replace! target start source)
(let ((len (string-length source)))
(do ((i (+ start len -1) (- i 1))
(j (- len 1) (- j 1)))
((< j 0) target)
(string-set! target i (string-ref source j)))))
;;; Copy SOURCE[source-start, source-end) into TARGET[start,)
(define (substring-replace! target start source source-start source-end)
(do ((i (+ start (- source-end source-start) -1) (- i 1))
(j (- source-end 1) (- j 1)))
((< j source-start) target)
(string-set! target i (string-ref source j))))
;;; Compute (... (f (f (f zero c0) c1) c2) ...)
(define (string-reduce f zero s)
(let ((len (string-length s)))
(let lp ((v zero) (i 0))
(if (= i len)
v
(lp (f v (string-ref s i)) (+ i 1))))))