[GHC] #9099: Add strict fmap

[GHC]

#9099: Add strict fmap
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       Reporter:  quchen                   |             Owner:
           Type:  feature request          |            Status:  new
       Priority:  normal                   |         Milestone:
      Component:  None                     |           Version:  7.8.2
       Keywords:                           |  Operating System:
   Architecture:  Unknown/Multiple         |  Unknown/Multiple
     Difficulty:  Easy (less than 1 hour)  |   Type of failure:
     Blocked By:                           |  None/Unknown
Related Tickets:                           |         Test Case:
                                           |          Blocking:
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 Add a strict version of fmap to the standard libraries.

 {{{
 infixl 4 <$!>

 (<$!>) :: Monad m => (a -> b) -> m a -> m b
 f <$!> m = do x <- m
               return $! f x
 {-# INLINE (<$!>) #-}
 }}}

 Libraries discussions:

 Take 1:
 http://www.haskell.org/pipermail/libraries/2013-November/021728.html
 Take 3: http://www.haskell.org/pipermail/libraries/2014-April/022864.html

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9099>
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