Hoogle Search
Within LTS Haskell 24.6 (ghc-9.10.2)
Note that Stackage only displays results for the latest LTS and Nightly snapshot. Learn more.
(
>>$ ) :: Arrow a => a b c -> d -> a b darrow-extras Control.Arrow.Extras postcomposition with a pure value
(
<$>! ) :: BEncode a => (a -> b) -> BKey -> Get bbencoding Data.BEncode (
<$>? ) :: BEncode a => (Maybe a -> b) -> BKey -> Get bbencoding Data.BEncode (
~$$~ ) :: b -> a -> (a -> b -> r) -> rbetween Data.Function.Between.Lazy Infix version of common pattern:
\f -> a `f` b -- Notice the order of 'a' and 'b'.
Since version 0.11.0.0.(
~$~ ) :: a -> b -> (a -> b -> r) -> rbetween Data.Function.Between.Lazy Infix version of common pattern:
\f -> a `f` b
Where a and b are fixed parameters. There is also prefix version named inbetween. Since version 0.11.0.0.(
~$$~ ) :: b -> a -> (a -> b -> r) -> rbetween Data.Function.Between.Strict Infix version of common pattern:
\f -> (f $! a) $! b -- Notice the order of 'a' and 'b'.
Since version 0.11.0.0.(
~$~ ) :: a -> b -> (a -> b -> r) -> rbetween Data.Function.Between.Strict Infix version of common pattern:
\f -> (f $! a) $! b
Where a and b are fixed parameters. There is also prefix version named inbetween. Since version 0.11.0.0.(
<$ ) :: Functor f => a -> f b -> f aclassy-prelude-yesod ClassyPrelude.Yesod Replace all locations in the input with the same value. The default definition is fmap . const, but this may be overridden with a more efficient version.
Examples
Perform a computation with Maybe and replace the result with a constant value if it is Just:>>> 'a' <$ Just 2 Just 'a' >>> 'a' <$ Nothing Nothing
(
<$> ) :: Functor f => (a -> b) -> f a -> f bclassy-prelude-yesod ClassyPrelude.Yesod An infix synonym for fmap. The name of this operator is an allusion to $. Note the similarities between their types:
($) :: (a -> b) -> a -> b (<$>) :: Functor f => (a -> b) -> f a -> f b
Whereas $ is function application, <$> is function application lifted over a Functor.Examples
Convert from a Maybe Int to a Maybe String using show:>>> show <$> Nothing Nothing
>>> show <$> Just 3 Just "3"
Convert from an Either Int Int to an Either Int String using show:>>> show <$> Left 17 Left 17
>>> show <$> Right 17 Right "17"
Double each element of a list:>>> (*2) <$> [1,2,3] [2,4,6]
Apply even to the second element of a pair:>>> even <$> (2,2) (2,True)
-
classy-prelude-yesod ClassyPrelude.Yesod A synonym for =$= for backwards compatibility. Since 0.4.0