[GHC] #4370: Bring back monad comprehensions

[GHC]

#4370: Bring back monad comprehensions
---------------------------------+------------------------------------------
    Reporter:  simonpj           |        Owner:  nsch        
        Type:  feature request   |       Status:  patch       
    Priority:  normal            |    Milestone:  7.4.1       
   Component:  Compiler          |      Version:  6.12.3      
    Keywords:                    |     Testcase:              
   Blockedby:                    |   Difficulty:              
          Os:  Unknown/Multiple  |     Blocking:              
Architecture:  Unknown/Multiple  |      Failure:  None/Unknown
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Comment(by nsch):

 I migrated all patches to git and resolved some conflicts. I also added a
 munzip to the `Control.Monad.Zip` module which is convenient to have and
 also is refered to in our paper.

 Files will get attached, the old ones should be ignored (there's no way to
 delete them?). Patching should be done via `git am <file>` where `<file>`
 is

  * `ghc-0001-monad-comprehensions-compiler.patch` and `ghc-0002-monad-
 comprehensions-user-guide.patch` in the ghc git root directory
  * `testsuite-0001-monad-comprehensions-test-suite.patch` in the
 `testsuite` git directory
  * `base-0001-monad-comprehensions-Group-and-Zip-monad.patch` in the
 `libraries/base` git directory
  * `Cabal-0001-monad-comprehensions-cabal-extensions.patch` in the
 `libraries/Cabal` git directory

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4370#comment:51>
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