On 12/1/19 5:55 AM, John Cowan wrote:
>     However, there is nothing preventing adding support for SRFI 122 storage classes
>     to SRFI 164.  For example one could add the procedure
>
>           (make-specialized-array SHAPE STORAGE-CLASS)
>
>     to SRFI 164 fairly easily, I'm pretty sure.
>
>
> Indeed.  Would you consider a revised SRFI or small extension incorporating storage classes (by reference, no need to copy them) and this procedure?

I wrote a simple pure-Kawa-Scheme implementation of make-specialized-array
and it seems to work.  (It won't work in Kawa head because of a name lookup bug
relating to 'int' (type) vs 'getInt' (method in AbstractSequence.  Haven't
yet decided on the best way to fix that.)

The key is a 'specialized-vector' class, which implements gvector
and delegates the various methods to a storage-class object.

(define (shape-size shape)
   ;; FIXME very inefficient
   (array-size (array (->shape shape) 0)))

(define-simple-class storage-class ()
   ((*init* getter setter checker maker length default)
    (set! (this):getter getter)
    (set! (this):setter setter)
    (set! (this):checker checker)
    (set! (this):maker maker)
    (set! (this):length length)
    (set! (this):default default))
   (getter ::procedure)
   (setter ::procedure)
   (checker ::procedure)
   (maker ::procedure)
   (length ::procedure)
   (default))

(define (make-storage-class getter setter checker maker length default)
   (storage-class getter setter checker maker length default))

(define-simple-class specialized-vector (gnu.lists.AbstractSequence
                                          gnu.lists.GVector)
   (sclass ::storage-class)
   (sz ::int)
   (vec ::gnu.lists.GVector)
   ((*init* size::int sclass::storage-class)
    (set! (this):sclass sclass)
    (set! sz size)
    (set! vec (sclass:maker size sclass:default)))
   ((get i::int) (sclass:getter vec i))
   ((getRaw i::int) (sclass:getter vec i))
   ((setRaw i::int val)::void (sclass:setter vec i val))
   ((size)::int sz))

(define (make-specialized-array shape sclass::storage-class)
   (set! shape (->shape shape))
   (array-reshape (specialized-vector (shape-size shape) sclass) shape))

(define generic-storage-class
   (make-storage-class vector-ref
                       vector-set!
                       (lambda (arg) #t)
                       make-vector
                       vector-length
                       #f))

--
	--Per Bothner
xxxxxx@bothner.com   http://per.bothner.com/