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Within LTS Haskell 24.33 (ghc-9.10.3)
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mapMOf :: LensLike (WrappedMonad m) s t a b -> (a -> m b) -> s -> m tmicrolens Lens.Micro Map each element of a structure targeted by a Lens to a monadic action, evaluate these actions from left to right, and collect the results.
>>> mapMOf both (\x -> [x, x + 1]) (1,3) [(1,3),(1,4),(2,3),(2,4)]
mapped :: Functor f => ASetter (f a) (f b) a bmicrolens Lens.Micro mapped is a setter for everything contained in a functor. You can use it to map over lists, Maybe, or even IO (which is something you can't do with traversed or each). Here mapped is used to turn a value to all non-Nothing values in a list:
>>> [Just 3,Nothing,Just 5] & mapped.mapped .~ 0 [Just 0,Nothing,Just 0]
Keep in mind that while mapped is a more powerful setter than each, it can't be used as a getter! This won't work (and will fail with a type error):[(1,2),(3,4),(5,6)] ^.. mapped . both
mapLeafBenchmarks :: ([String] -> Benchmark -> Benchmark) -> Benchmark -> Benchmarktasty-bench Test.Tasty.Bench Map leaf benchmarks (bench, not bgroup) with a provided function, which has an access to leaf's reversed path. This helper is useful for bulk application of bcompare. See also locateBenchmark. Real world examples:
map' :: (Mapping p, Functor f) => p a b -> p (f a) (f b)profunctors Data.Profunctor Laws:
map' . rmap f ≡ rmap (fmap f) . map' map' . map' ≡ dimap Compose getCompose . map' dimap Identity runIdentity . map' ≡ id
map' :: (Mapping p, Functor f) => p a b -> p (f a) (f b)profunctors Data.Profunctor.Mapping Laws:
map' . rmap f ≡ rmap (fmap f) . map' map' . map' ≡ dimap Compose getCompose . map' dimap Identity runIdentity . map' ≡ id
mapParseError :: Ord e' => (e -> e') -> ParseError s e -> ParseError s e'megaparsec Text.Megaparsec.Error Modify the custom data component in a parse error. This could be done via fmap if not for the Ord constraint.
mapMaybeM :: Monad m => (a -> m (Maybe b)) -> [a] -> m [b]extra Control.Monad.Extra A version of mapMaybe that works with a monadic predicate.
mapLeft :: (a -> c) -> Either a b -> Either c bextra Data.Either.Extra The mapLeft function takes a function and applies it to an Either value iff the value takes the form Left _.
mapLeft show (Left 1) == Left "1" mapLeft show (Right True) == Right True
mapRight :: (b -> c) -> Either a b -> Either a cextra Data.Either.Extra The mapRight function takes a function and applies it to an Either value iff the value takes the form Right _.
mapRight show (Left 1) == Left 1 mapRight show (Right True) == Right "True"
mapLeft :: (a -> c) -> Either a b -> Either c bextra Extra The mapLeft function takes a function and applies it to an Either value iff the value takes the form Left _.
mapLeft show (Left 1) == Left "1" mapLeft show (Right True) == Right True