Difference between revisions of "Implicit parameters"
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The GHC manual on implicit parameters: [http://www.haskell.org/ghc/docs/latest/html/users_guide/other-type-extensions.html#implicit-parameters]. |
The GHC manual on implicit parameters: [http://www.haskell.org/ghc/docs/latest/html/users_guide/other-type-extensions.html#implicit-parameters]. |
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| + | Working example: |
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| + | {-# LANGUAGE ImplicitParams #-} |
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| + | import Data.List (sortBy) |
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| + | sort :: (?cmp :: a -> a -> Ordering) => [a] -> [a] |
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| + | sort = sortBy ?cmp |
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| + | main = let ?cmp = compare in putStrLn (show (sort [3,1,2])) |
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[[Category:Language extensions]] |
[[Category:Language extensions]] |
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Revision as of 18:41, 18 December 2012
The GHC manual on implicit parameters: [1].
Working example:
{-# LANGUAGE ImplicitParams #-}
import Data.List (sortBy)
sort :: (?cmp :: a -> a -> Ordering) => [a] -> [a]
sort = sortBy ?cmp
main = let ?cmp = compare in putStrLn (show (sort [3,1,2]))