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Within LTS Haskell 24.6 (ghc-9.10.2)
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mapPoints :: Ord v => (Point u -> Point v) -> Bitmap u p -> Bitmap v phaha Graphics.Ascii.Haha.Bitmap No documentation available.
mapSubject :: (b -> a) -> SpecWith a -> SpecWith bhspec-meta Test.Hspec.Meta Modify the subject under test. Note that this resembles a contravariant functor on the first type parameter of SpecM. This is because the subject is passed inwards, as an argument to the spec item.
mapFB :: (elt -> lst -> lst) -> (a -> elt) -> a -> lst -> lstihaskell IHaskellPrelude No documentation available.
mappend :: Monoid a => a -> a -> aihaskell IHaskellPrelude An associative operation NOTE: This method is redundant and has the default implementation mappend = (<>) since base-4.11.0.0. Should it be implemented manually, since mappend is a synonym for (<>), it is expected that the two functions are defined the same way. In a future GHC release mappend will be removed from Monoid.
mapAccumL :: Traversable t => (s -> a -> (s, b)) -> s -> t a -> (s, t b)incipit-base Incipit.Base The mapAccumL function behaves like a combination of fmap and foldl; it applies a function to each element of a structure, passing an accumulating parameter from left to right, and returning a final value of this accumulator together with the new structure.
Examples
Basic usage:>>> mapAccumL (\a b -> (a + b, a)) 0 [1..10] (55,[0,1,3,6,10,15,21,28,36,45])
>>> mapAccumL (\a b -> (a <> show b, a)) "0" [1..5] ("012345",["0","01","012","0123","01234"])mapAccumR :: Traversable t => (s -> a -> (s, b)) -> s -> t a -> (s, t b)incipit-base Incipit.Base The mapAccumR function behaves like a combination of fmap and foldr; it applies a function to each element of a structure, passing an accumulating parameter from right to left, and returning a final value of this accumulator together with the new structure.
Examples
Basic usage:>>> mapAccumR (\a b -> (a + b, a)) 0 [1..10] (55,[54,52,49,45,40,34,27,19,10,0])
>>> mapAccumR (\a b -> (a <> show b, a)) "0" [1..5] ("054321",["05432","0543","054","05","0"])mapM :: (Traversable t, Monad m) => (a -> m b) -> t a -> m (t b)incipit-base Incipit.Base Map each element of a structure to a monadic action, evaluate these actions from left to right, and collect the results. For a version that ignores the results see mapM_.
Examples
mapM is literally a traverse with a type signature restricted to Monad. Its implementation may be more efficient due to additional power of Monad.mapMaybe :: (a -> Maybe b) -> [a] -> [b]incipit-base Incipit.Base The mapMaybe function is a version of map which can throw out elements. In particular, the functional argument returns something of type Maybe b. If this is Nothing, no element is added on to the result list. If it is Just b, then b is included in the result list.
Examples
Using mapMaybe f x is a shortcut for catMaybes $ map f x in most cases:>>> import GHC.Internal.Text.Read ( readMaybe ) >>> let readMaybeInt = readMaybe :: String -> Maybe Int >>> mapMaybe readMaybeInt ["1", "Foo", "3"] [1,3] >>> catMaybes $ map readMaybeInt ["1", "Foo", "3"] [1,3]
If we map the Just constructor, the entire list should be returned:>>> mapMaybe Just [1,2,3] [1,2,3]
mappend :: Monoid a => a -> a -> aincipit-base Incipit.Base An associative operation NOTE: This method is redundant and has the default implementation mappend = (<>) since base-4.11.0.0. Should it be implemented manually, since mappend is a synonym for (<>), it is expected that the two functions are defined the same way. In a future GHC release mappend will be removed from Monoid.
mapM_ :: (Foldable t, Monad m) => (a -> m b) -> t a -> m ()incipit-base Incipit.Foldable Map each element of a structure to a monadic action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see mapM. mapM_ is just like traverse_, but specialised to monadic actions.