[GHC] #12477: Allow left sectioning and tuple sectioning of types

[GHC]

#12477: Allow left sectioning and tuple sectioning of types
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        Reporter:  Iceland_jack      |                Owner:  Iceland_jack
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              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):

 In the wild
 [https://www.reddit.com/r/haskell/comments/4z28nk/tear_down_cofree/d6sbmwr
 wild]:

 > For example, if you have a stream of values, `given by Cofree (, a)`,
 then you can use the free monad for `(a ->)` to extract a value at some
 index. At each step, you can either `return` a function to extract a value
 from the current position in the comonad, or `liftF` a function which
 tells you how to handle the next value in the stream.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12477#comment:4>
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