Eduardo Cavazos wrote:
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)))))
This is a simulation of what systems like Larceny offer. I.e. you call
'procedure-arity' on a procedure object.
I think there are other, but perhaps more "far out" approaches to this.
For example, consider a version of 'procedure-arity' which actually take
the *name* of a procedure as a symbol:
(define (procedure-arity f)
(cdr (assq f '((vector-ref . 2)
(vector-set! . 3)
(eq? . 2)))))
A macro (like smart-curry) would have no trouble at all with this. But
of course, now you might not be getting the right information since
there may be many procedures named 'vector-ref' from various libraries.
How would a table like 'procedure-arity' get populated? A define-like
macro could annotate the table.
I know very little about the implementation of syntax, macros, etc. But
occasionally I see discussion regarding "syntactic information" being
attached to symbols. So I wonder if another route is as follows; when
defining a procedure, attach information to that symbol which indicates
that is *is* a procedure with certain properties; arity, how many values
it produces, the body as an sexp, etc. This is information that *can* be
used by macros.
Ed
