On Sun, May 31, 2009 at 7:10 PM, Manuel M T Chakravarty wrote:

Lee Duhem:

...

On Sat, May 30, 2009 at 7:35 PM, Maurí cio 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.

There is also special syntax to export associated types.  You can write

 MyClass (type T)

in the export list; cf,

 http://haskell.org/haskellwiki/GHC/Type_families#Import_and_export

This is a better way. lee