[GHC] #4517: Add Data.Functor.Backwards to transformers

[GHC]

#4517: Add Data.Functor.Backwards to transformers
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    Reporter:  r6                |       Owner:                   
        Type:  proposal          |      Status:  new              
    Priority:  normal            |   Component:  libraries (other)
     Version:  7.0.1             |    Keywords:  backwards        
    Testcase:                    |   Blockedby:                   
          Os:  Unknown/Multiple  |    Blocking:                   
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown     
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 Data.Functor.Backwards is a wrapper for functors that allow Foldable,
 Traversable, and Applicative functors to be operated backwards.  It is
 similar to Dual for Monoids.  The Applicative instance runs effects in
 reversed order.  The Foldable instance folds from right to left, The
 Traversable instance traverses from right to left.

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4517>
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