Well, I think that's because MyList had a different kind than List. List is a type constructor but not a type. MyList, on the other hand, is a (polymorphic) type, and it can't be applied; rather, its type variables need to be instantiated. Though, given its definition, I don't see how you could instantiate all of them.
> On Jun 17, 2014, at 8:48 PM, "Alexander D. Knauth" <alexan...@knauth.org> > wrote: > > Could you represent it with something like (All (a …) (List a … a))? > > From reading the documentation it seems like it should work, but > When I tried it, I got this: > > #lang typed/racket > > (define-type MyList (All (a ...) (List a ... a))) > > (ann '(1 2 3) (MyList 1 2 3)) > > . Type Checker: Type MyList cannot be applied, arguments were: (One 2 3) in: > (MyList 1 2 3) > >> On Jun 17, 2014, at 8:33 PM, J. Ian Johnson <i...@ccs.neu.edu> wrote: >> >> I imagine it's because there are no variable-arity type constructors in TR, >> and (List A ...) is fancy syntax for (Pairof A (Pairof ... '()) ...) if >> that notation makes any sense. >> -Ian >> ----- Original Message ----- >> From: "Spencer Florence" <spen...@florence.io> >> To: "racket" <users@racket-lang.org> >> Sent: Tuesday, June 17, 2014 5:32:55 PM GMT -05:00 US/Canada Eastern >> Subject: [racket] define-type on List and Listof >> >> >> >> Hi all, >> >> I'm trying to rename some types in typed/racket but something odd is >> happening: >> >> >> (define-type A Listof) >> >> works but: >> >> >> (define-type B List) >> >> errors with "Type Checker: parse error in type; type name `List' is unbound >> in: List" >> >> Is this a bug or am I missing something? >> >> --Spencer >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users > > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
