[Haskell-cafe] ANNOUNCE fmlist

[Sjoerd Visscher]

On Jun 19, 2009, at 3:35 PM, Sjoerd Visscher wrote:

> > transform t l = FM $ \f -> unFM l (t f)
>
> Unfortunately I couldn't get this code to type-check, so the library  
> doesn't use transform.


With some help from Martijn van Steenbergen the type turned out to be:

transform :: (forall b. Monoid b => (a -> b) -> (c -> b)) -> FMList c - 
 > FMList a

I've updated the library to use the transform function.
--
Sjoerd Visscher
sjoerd at w3future.com