[GHC] #13026: RFC functions for sums and products

[GHC]

#13026: RFC functions for sums and products
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        Reporter:  Iceland_jack      |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  libraries/base    |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Iceland_jack):

 Purescript also includes this function for `Data.Functor.Compose`

 {{{#!hs
 bihoistCompose
   :: forall f g h i
    . Functor f
   => (f ~> h)
   -> (g ~> i)
   -> Compose f g
   ~> Compose h i
 bihoistCompose natF natG (Compose fga) = Compose (natF (map natG fga))
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13026#comment:7>
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