On 5/24/22 4:39 PM, Bradley Lucier wrote:

> Which brought to mind whether keyword arguments would be best for
> specifying the argument list for make-specialized-array:
>
> (define (make-specialized-array
>           interval
>           #!key
>           (storage-class (generic-storage-class))
>           (initial-value (storage-class-default storage-class))
>           (mutable?      (specialized-array-default-mutable?))
>           (safe?         (specialized-array-default-safe?)))
>    ...)
>
> Are keyword arguments widely enough supported for this to be a good
> thing to do?
>
> If not, which argument order would be better?

Keyword arguments seem to make it easier to use, and easier to code.
Here's a version (untested) using keywords:

(define (make-specialized-array interval
                                 #!rest rest
                                 #!key
                                 (storagae-class generic-storage-class)
                                 (initial-value (if (storage-class?
storage-class) (storage-class-default storage-class) #f)) ;; error in
storage-class will be caught later
                                 (safe? (specialized-array-default-safe?)))
   (cond ((not (storage-class? storage-class))
          (apply error "make-specialized-array: storage-class is not a
known storage class: " interval rest))
         ((not ((storage-class-checker storage-class) initial-value))
          (apply error "make-specialized-array: initial-value cannot be
manipulated by the storage class: " interval rest))
         ((not (boolean? safe?))
          (apply error "make-specialized-array: safe? is not a boolean:
" interval rest))
         (else
          (%%make-specialized-array interval
                                        initial-value
                                        storage-class
                                        safe?))))

and here's the current version using case-lambda:

(define make-specialized-array
   (let ()
     (define (one-arg interval initial-value storage-class safe?)
       (cond ((not (interval? interval))
              (error "make-specialized-array: The first argument is not
an interval: "
                     interval))
             (else
              (%%make-specialized-array interval
                                        initial-value
                                        storage-class
                                        safe?))))
     (define (three-args interval initial-value storage-class safe?)
       (cond ((not (storage-class? storage-class))
              (error "make-specialized-array: The third argument is not
a storage-class: "
                     interval initial-value storage-class))
             ((not ((storage-class-checker storage-class) initial-value))
              (error "make-specialized-array: The second argument cannot
be manipulated by the third (a storage class): "
                     interval initial-value storage-class))
             (else
              (one-arg interval
                       initial-value
                       storage-class
                       safe?))))
     (define (four-args interval initial-value storage-class safe?)
       (cond ((not (boolean? safe?))
              (error "make-specialized-array: The fourth argument is not
a boolean: "
                     interval initial-value storage-class safe?))
             (else
              (three-args interval
                          initial-value
                          storage-class
                          safe?))))
     (case-lambda
      ((interval)
       (one-arg interval
                (storage-class-default generic-storage-class)
                generic-storage-class
                (specialized-array-default-safe?)))
      ((interval initial-value)
       (one-arg interval
                initial-value
                generic-storage-class
                (specialized-array-default-safe?)))
      ((interval initial-value storage-class)
       (three-args interval
                   initial-value
                   storage-class
                   (specialized-array-default-safe?)))
      ((interval initial-value storage-class safe?)
       (four-args interval
                  initial-value
                  storage-class
                  safe?)))))