And what do you say to this: > I admit that that error just makes my eyes glaze over, but I'm pretty sure > that the problem here is that TR can't reduce this filter type, and just > needs a cleverness injection.
-- Matthias On Jan 30, 2012, at 3:54 PM, Sam Tobin-Hochstadt wrote: > On Mon, Jan 30, 2012 at 3:48 PM, John Clements > <cleme...@brinckerhoff.org> wrote: >> >> Looking at this, though, it seems to me that it might be simpler just to ask >> TR to construct a filter for a given type, and it occurs to me that this >> might already be built-in. If so, I can't find it in the documentation. > > What you want is `define-predicate': > > #lang typed/racket > > (define-type GradeElement > (Pair Bytes Null)) > > ;; this line is not required > (: grade-element? (Any -> Boolean : GradeElement)) > (define-predicate grade-element? GradeElement) > > Docs here: > http://docs.racket-lang.org/ts-reference/special-forms.html#%28form._%28%28lib._typed-racket/base-env/prims..rkt%29._define-predicate%29%29 > > -- > sam th > sa...@ccs.neu.edu > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
