Hello,
Let's simulate 'procedure-arity' functionality for a few procedures:
(define (procedure-arity f)
(cdr (assq f (list (cons vector-ref 2)
(cons vector-set! 3)
(cons eq? 2)))))
Here's a basic curry macro:
(define-syntax curry
(syntax-rules ()
((curry (f x)) f)
((curry (f x y ...))
(lambda (x)
(curry ((lambda (y ...)
(f x y ...))
y ...))) )))
You have to specify the arity of the thing you're currying. For example:
(curry (vector-set! x y z))
will give you a curried 'vector-set!'.
Below is some pseudo-code for a "smart-curry" which uses
procedure-arity. Is something like it possible?
(define-syntax smart-curry
(lambda (stx)
(syntax-case stx ()
((smart-curry f)
(with-syntax (((x ...) (generate-temporaries
(iota
(procedure-arity f)))))
(syntax (curry (f x ...))))))))
I guess it comes down to, can a macro "eval" that 'f' so that it's a
procedure which can then be passed to 'procedure-arity'?
Or is there another approach to something like this?
If stuff like this *is* possible, then I think it's makes a case for
'procedure-arity'.
Ed
