Re: relationship to SRFI-25 Bradley Lucier 28 Sep 2015 22:38 UTC

On 09/28/2015 06:22 PM, Jamison Hope wrote:
> On Sep 28, 2015, at 5:53 PM, Bradley Lucier <xxxxxx@math.purdue.edu> wrote:
>
>> (4) when using this array API there is no point in this whole process where a bang occurs textually.
>
> This could be resolved quite easily if the API provided array-set! instead
> of just array-setter.  I hesitate to suggest adding more procedures to the
> API, since I think there are already too many, but it would feel much more
> natural if there were array-get and array-set! procedures that called
> array-getter and array-setter under the hood.

Here are those procedures:

(define (array-ref a . args)
   (apply (array-getter a) args))

(define (array-set! a v . args)
   (apply (array-setter a) v args))

 From my point of view these procedures achieve very little (accessing
or setting one value in an array) with either (1) the cost of a lot of
error checking, (2) the dangers of no error checking, and (3) the cost
of calling apply.

I could go through and look at the dimension of the domain of a and
specialize the calling sequence for small dimensions to avoid using
apply.  That would add a dozen lines of code.

But that's exactly the same kind of checking and specialization that is
needed for array-map, array-reduce, or any of the other full array
operations.  That checking  and specialization is done *once*, and
benefit the operations on *all* the elements of the array.  I hope that
some of this is understandable from the reference implementation.

I don't find that these word-by-word operations are helpful for my codes
(which I consider to be real codes).

Brad