On 4/12/06, Scott Weeks <[EMAIL PROTECTED]> wrote: > Hello everyone, > > I've been banging my head against my desk a bit so I figured it's time > to ask for help :-) > > When a user queries I have to read the input from IO and then somehow > cast the key/index type without angering the type checker. If I omit > the following function I get the ominous "Ambiguous type variable a..." > error. If I use it I get a complaint that the checker was expecting an > Integer rather than a PackedString.
Well, if you get an "ambiguous type variable" error, you probably (I think) need to add some type annotations. For example: class Foo a where foo :: a bar :: a -> String Evaluating bar foo will result in an error, but bar (foo :: Integer) will work just fine. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe