[GHC] #2329: Control.Parallel.Strategies: definitions of rnf for most collections are poor

[GHC]

#2329: Control.Parallel.Strategies: definitions of rnf for most collections are
poor
-----------------------------------------+----------------------------------
    Reporter:  bos                       |       Owner:                
        Type:  run-time performance bug  |      Status:  new           
    Priority:  normal                    |   Component:  libraries/base
     Version:  6.8.2                     |    Severity:  normal        
    Keywords:                            |    Testcase:                
Architecture:  Unknown                   |          Os:  Unknown       
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 These all perform a lot of consing, which seems rather undesirable.  It
 would be very nice indeed if they could be rebaked in terms of strict left
 folds.  Unfortunately, all of the collections in question seem only to
 expose non-strict left folds publicly.

 {{{
 instance (NFData k, NFData a) => NFData (Data.Map.Map k a) where
     rnf = rnf . Data.Map.toList

 instance NFData a => NFData (Data.Set.Set a) where
     rnf = rnf . Data.Set.toList

 instance NFData a => NFData (Data.Tree.Tree a) where
     rnf (Data.Tree.Node r f) = rnf r `seq` rnf f

 instance NFData a => NFData (Data.IntMap.IntMap a) where
     rnf = rnf . Data.IntMap.toList

 instance NFData Data.IntSet.IntSet where
     rnf = rnf . Data.IntSet.toList
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2329>
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