Tomislav Mutak <mutakti@rose-hulman.edu> wrote:
+---------------
| I'm trying to make a distinct copy of a vector...
|    (list->vector (vector->list original))
| I just know there is a better/more efficient way to do this...?
+---------------

Well, rather than spread that idiom throughout your code, I'd at least say:

	(define (vector-copy v)
	  (list->vector (vector->list v)))

But, yes, that probably *is* the simplest/best way using the primitives
provided in the R5RS spec, since there's no "vector-copy" there. I suppose
you could that version with this one:

	(define (vector-copy old)
	  (let* ((len (vector-length old))
	         (new (make-vector len)))
	    (do ((i 0 (+ i 1)))
		((>= i len))
	      (vector-set! new i (vector-ref old i)))
	    new))

However, this may or may not be faster and/or more space-efficient,
depending on the details of your system's garbage collector (e.g., is
it a generational/copying collector? -- in which case using mutation
might slow down future collections) or compiler (which might recognize
that idiom) or library (which might already have a "vector-copy" in it).

-Rob

-----
Rob Warnock, 31-2-510		rpw3@sgi.com
SGI Network Engineering		http://reality.sgi.com/rpw3/
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