Dear list members,
As an exercise to learn Racket macros I'm setting up macros as getters
and setters on multi-dimensional arrays where the array reference is
array[dimension1 dimension2 ...]
This is useful for my application but the main reason is to learn macros.
I'm able to set up getter and setter macros using syntax-rules as follows:
--------------------------------------------------
(define v1 (vector
(vector (vector 1 2 3)
(vector 11 22 33)
(vector 111 222 333))
(vector (vector 1 2 3)
(vector 11 22 33)
(vector 111 222 333))))
(define-syntax get-array-element
(syntax-rules ()
[(get-array-element v[d1]) (vector-ref v d1)]
[(get-array-element v[d1 d2 ...] ) (get-array-element (vector-ref
v d1)[d2 ...] )]))
(define-syntax set-array-element!
(syntax-rules ()
[(set-array-element! v[d1] exp) (vector-set! v d1 exp)]
[(set-array-element! v[d1 d2 ...] exp) (set-array-element!
(vector-ref v d1)[d2 ...]exp)]))
(get-array-element v1[1 1 1])
(set-array-element! v1[1 1 0] 999999)
-------------------------------------------------
which works just fine but when I try the following using syntax-id-rules:
(define-syntax array-element
(syntax-id-rules (get set!)
[(get array-element v[d1]) (vector-ref v d1)]
[(get array-element v[d1 d2 ...] ) (get array-element
(vector-ref v d1)[d2 ...] )]
[(set! array-element v[d1] exp) (vector-set! v d1 exp)]
[(set! array-element v[d1 d2 ...] exp) (set! array-element
(vector-ref v d1)[d2 ...]exp)]))
(get array-element v1[1 1 1])
(set! array-element v1[1 1 0] 999999)
-------------------------------------------------------
I get the error for (get array-element v1[1 1 1] "expand: unbound
identifier in module in: get"
and for (set! array-element v1[1 1 1] I get the error of: "set!: bad
syntax (has 4 parts after keyword) in: (set! array-element v1 (1 1 0)
999999)"
Using syntax-id-rules is there a way to write my array-element macro so that :
(get array-element v1[1 1 1])
(set! array-element v1[1 1 0] 999999)
work correctly without the "get" and "set!" identifiers giving me errors.
I know I can write get and set! macros using syntax-rules to do this,
but I'm doing this mainly as a learning exercise about
syntax-id-rules.
Many thanks,
Harry Spier
_________________________________________________
For list-related administrative tasks:
http://lists.racket-lang.org/listinfo/users
