On 3/16/23 5:54 PM, John Cowan wrote:
That pushes matters along a little further: you get the right behavior
if the array is specialized.
Well, specialized and the elements are contiguous and in order.
However, it's not clear to me why
generalized arrays can't be reshaped, or why non-affine transforms
expressed as reshapes require eager copying, rather than a lazy
operation similar to mapping.
One can do that in SRFI 231, but one would have to write the transform
oneself. I.e., if
> (define A (make-array (make-interval '#(2 4 5)) list))
> (define B (make-array (make-interval '#(40))
(let ((A_ (array-getter A)))
(lambda (i)
(A_ (quotient i 20)
(quotient (modulo i 20) 5)
(modulo i 5))))))
> (equal? (array->vector A) (array->vector B))
#t
And B is a generalized array out, not a specialized array. (Of course,
A itself is generalized.)
This appears similar to SRFI 164/Kawa's array-transform.
Brad
