Lexically scoped type variables

Christian Maeder maeder at tzi.de
Mon Feb 6 08:34:05 EST 2006

Simon Peyton-Jones wrote:
> I took a look.  Here's a typical example:
> newVariableListFromSet :: Ord a => VariableSetSource a -> VariableList a
> newVariableListFromSet (variableSetSource :: VariableSetSource a) =
>    let
>       attachListOp parallelX (listDrawer :: ListDrawer a pos) =
>          do
>             (posRegistry :: Registry a pos) <- newRegistry

> To fix this you'd need to

> b) Add a type signature for attachListOp, beginning with forall pos.

That was exactly my problem. How should I find out the type of 
attachListOp (I have not written this bit of code)? Could I somehow ask 
ghci-6.4.1 to do it for me?

Thanks for looking into it, Christian

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