Set, Map libraries
Robert van Herk
rherk at cs.uu.nl
Thu Jun 2 03:48:33 EDT 2005
>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
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 ...
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