[GHC] #10976: Applicative Comprehensions

[GHC]

#10976: Applicative Comprehensions
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        Reporter:  davidar           |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:  8914
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Description changed by thomie:

Old description:

> As discussed on `ghc-devs`, when both the `MonadComprehensions` and
> `ApplicativeDo` language extensions are enabled, it should be possible to
> use comprehension-notation (in addition to do-notation) for
> `Applicative`s. This would allow, for example, an expression like
>
> {{{#!hs
> (\x y -> x + 2*y) <$> ZipList [1..10] <*> ZipList [10,20..100]
> }}}
>
> to also be written as
>
> {{{#!hs
> [ x + 2*y | x <- ZipList [1..10], y <- ZipList [10,20..100] ]
> }}}

New description:

 As discussed on [https://mail.haskell.org/pipermail/ghc-
 devs/2015-October/010062.html ghc-devs], when both the
 `MonadComprehensions` and `ApplicativeDo` language extensions are enabled,
 it should be possible to use comprehension-notation (in addition to do-
 notation) for `Applicative`s. This would allow, for example, an expression
 like

 {{{#!hs
 (\x y -> x + 2*y) <$> ZipList [1..10] <*> ZipList [10,20..100]
 }}}

 to also be written as

 {{{#!hs
 [ x + 2*y | x <- ZipList [1..10], y <- ZipList [10,20..100] ]
 }}}

--

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10976#comment:1>
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