Any reason the libaries don't define: class HasNull a where null::a->Bool class HasEmpty a where empty::a I find that I sometimes switch between using lists, sets, or tables as my collection type and the forced import qualifification for generic collection operations seems annoying. -Alex- On Thu, 2 Jun 2005, Robert van Herk wrote:
6. My module applies Data.Set.null (s :: Set a), and null (xs :: [a]).
Why ghc reports of the clash with GHC.List.null ? Is GHC.List same as old List library module? Should I write import GHC.List (genericLength, null) instead of import List (genericLength) ?
As the documentation reads:
This module is intended to be imported qualified, to avoid name clashes with Prelude http://www.haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html functions. eg.
import Data.Set as Set
So, you should write:
import qualified Data./x/ as /y/
Now, no name clashes will occur. However, you will have to write /y/.null to access null in /x/, for example:
import qualified Data.Set as Set
if (Set.null ...) then ... else ...
Regards, Robert _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
______________________________________________________________ S. Alexander Jacobson tel:917-770-6565 http://alexjacobson.com