[Haskell-cafe] Type families in export lists

Lee Duhem lee.duhem at gmail.com
Sat May 30 11:23:28 EDT 2009

On Sat, May 30, 2009 at 7:35 PM, Maurí­cio <briqueabraque at yahoo.com> wrote:
> Hi,
> How do I include type families (used as associated
> types) in a module export list? E.g.:
> class MyClass a where
>    type T a :: *
>    coolFunction :: Ta -> a
>    (...)
> If I just include MyClass and its functions in the
> list, instances in other modules complain they don't
> know T, but I wasn't able to find how (where) to
> include T in the list.

In export list, you can treat 'type T a' as normal type declaration, ie, write
T(..)  in export list.


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