[GHC] #9759: Add Alternative wrapper to Data.Monoid
#9759: Add Alternative wrapper to Data.Monoid -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: dfeuer Type: task | Status: new Priority: normal | Milestone: 7.10.1 Component: Core Libraries | Version: 7.9 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Easy (less than 1 | Type of failure: hour) | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- As discussed on the libraries list, {{{#!hs -- | Monoid under @<|>@. newtype Alt f a = Alt {getAlt :: f a} deriving (Generic, Generic1, Read, Show, Eq, Ord, Num, Enum, Monad, MonadPlus, Applicative, Alternative, Functor) instance forall f a . Alternative f => Monoid (Alt f a) where mempty = Alt empty mappend = coerce ((<|>) :: f a -> f a -> f a) }}} The documentation for `Data.Monoid.First` and `Data.Monoid.Last` should also be expanded to explain that `First a` is isomorphic to `Alt Maybe a` and `Last a` is isomorphic to `Dual (Alt Maybe a)`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9759 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9759: Add Alternative wrapper to Data.Monoid -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: dfeuer Type: task | Status: patch Priority: normal | Milestone: 7.10.1 Component: Core | Version: 7.9 Libraries | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Easy (less than 1 Unknown/Multiple | hour) Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | Blocking: | Differential Revisions: Phab:D422 | -------------------------------------+------------------------------------- Changes (by dfeuer): * status: new => patch * differential: => Phab:D422 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9759#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9759: Add Alternative wrapper to Data.Monoid -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: dfeuer Type: task | Status: patch Priority: normal | Milestone: 7.10.1 Component: Core | Version: 7.9 Libraries | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Easy (less than 1 Unknown/Multiple | hour) Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | Blocking: | Differential Revisions: Phab:D422 | -------------------------------------+------------------------------------- Comment (by dfeuer): Mailing list thread supporting addition: https://www.haskell.org/pipermail/libraries/2014-October/024045.html -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9759#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9759: Add Alternative wrapper to Data.Monoid
-------------------------------------+-------------------------------------
Reporter: dfeuer | Owner: dfeuer
Type: task | Status: patch
Priority: normal | Milestone: 7.10.1
Component: Core | Version: 7.9
Libraries | Keywords:
Resolution: | Architecture: Unknown/Multiple
Operating System: | Difficulty: Easy (less than 1
Unknown/Multiple | hour)
Type of failure: | Blocked By:
None/Unknown | Related Tickets:
Test Case: |
Blocking: |
Differential Revisions: Phab:D422 |
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Comment (by Herbert Valerio Riedel
#9759: Add Alternative wrapper to Data.Monoid -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: dfeuer Type: task | Status: closed Priority: normal | Milestone: 7.10.1 Component: Core | Version: 7.9 Libraries | Keywords: Resolution: fixed | Architecture: Unknown/Multiple Operating System: | Difficulty: Easy (less than 1 Unknown/Multiple | hour) Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | Blocking: | Differential Revisions: Phab:D422 | -------------------------------------+------------------------------------- Changes (by thomie): * status: patch => closed * resolution: => fixed -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9759#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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