vectors.sls

#!r6rs
;; Copyright 2009 Derick Eddington.  My MIT-style license is in the file named
;; LICENSE from the original collection this file is distributed with.

(library (xitomatl vectors)
  (export
    subvector)
  (import
    (rnrs)
    (only (xitomatl define) define/?/AV)
    (only (xitomatl predicates) exact-integer?))
  
  (define/?/AV (subvector (v vector?) (start exact-integer?) (end exact-integer?)) 
    (let ((len (vector-length v)))
      (unless (<= 0 start end len)
        (AV "invalid indices" start end v))
      (let ((n (make-vector (- end start))))
        (let loop ((x 0)
                   (y start))
          (cond ((= y end)
                 n)
                (else
                 (vector-set! n x (vector-ref v y))
                 (loop (+ 1 x) (+ 1 y))))))))

)