On Mon, Apr 18, 2011 at 3:02 PM, Jeremiah Willcock <[email protected]> wrote: > Given the following Typed Racket program: > > #lang typed/racket > > (: greater-than-5? (Any -> Boolean)) > (define (greater-than-5? x) > (and (integer? x) (> x 5)))
First, you probably want to use `exact-integer?' here, see the TR docs for `Integer'. > (: equal-to-7? (Any -> Boolean)) > (define (equal-to-7? x) > (and (greater-than-5? x) (= x 7))) > > I receive the error (highlighting the x in (= x 7)): > > Type Checker: Expected Complex, but got Any in: x > > Is there a way to tag greater-than-5? to mark that it only returns #t on > integers? Marking its type as (Any -> Boolean : Integer) causes an error: > > Type Checker: Expected result with filter ((Integer @ x) | (! Integer @ x)), > got filter (((U Float Integer) @ x) | (OrFilter (! Integer @ x) ((U Float > Integer) @ x))) in: (and (integer? x) (> x 5)) Second, there isn't currently a way to write this, because I haven't found a notation I like. It's something I want to do fairly soon, though. -- sam th [email protected] _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
