[Series-users] Alteration not working for my scanner.

[Dirk G. <di...@di...>]

Hi,

does anyone know what I'm doing wrong in the following code?  I'm trying
to make a scanner for a 3D vector data structure that supports
alteration.  As you can see the scanning works fine, but ALTER has no
effect:

> (defstruct vec x y z)
VEC
> (defun scan-vec (vec)
    (declare (optimizable-series-function))
    (to-alter (make-series (vec-x vec) (vec-y vec) (vec-z vec))
              #'(lambda (new-value index)
                  (ecase index
                    (0 (setf (vec-x vec) new-value))
                    (1 (setf (vec-x vec) new-value))
                    (2 (setf (vec-x vec) new-value))))
              (scan-range :from 0)))
SCAN-VEC
> (collect (scan-vec (make-vec :x 1 :y 2 :z 3)))
(1 2 3)
> (let ((vec (make-vec :x 1 :y 2 :z 3)))
    (alter (scan-vec vec) (series 0))
    vec)
#S(VEC :X 1 :Y 2 :Z 3)    ; <-- should be #S(VEC :X 0 :Y 0 :Z 0)

I'm using the dev-lisp/cl-series-2.2.7 package in Gentoo Linux.  This
contains some patches of mine to make it work for SBCL, but I've also
tried the above in CMUCL with the same results.

Thanks in advance for any help.

Kind regards,

Dirk Gerrits