Hoogle Search
Within LTS Haskell 24.3 (ghc-9.10.2)
Note that Stackage only displays results for the latest LTS and Nightly snapshot. Learn more.
(
<$> ) :: Functor f => (a -> b) -> f a -> f bshelly Shelly 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 <$> (2,2) (2,True)
(
<$> ) :: Functor f => (a -> b) -> f a -> f bshelly Shelly.Lifted 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 <$> (2,2) (2,True)
(
<$> ) :: Functor f => (a -> b) -> f a -> f bshelly Shelly.Pipe 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 <$> (2,2) (2,True)
(
<$> ) :: Functor f => (a -> b) -> f a -> f bturtle Turtle 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 <$> (2,2) (2,True)
(
<$>^ ) :: (a -> b) -> f a -> Aps f bap-normalize ApNormalize f <$>^ u :: Aps f b is a delayed representation of f <$> u :: f b, so that it can be fused with other applicative operations. f <$>^ u is a shorthand for f <$> liftAps u.
(
<$>^ ) :: (a -> b) -> f a -> Aps f bap-normalize ApNormalize.Aps f <$>^ u :: Aps f b is a delayed representation of f <$> u :: f b, so that it can be fused with other applicative operations. f <$>^ u is a shorthand for f <$> liftAps u.
(
<$ ) :: Functor f => a -> f b -> f abase-prelude BasePrelude.Operators 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 bbase-prelude BasePrelude.Operators 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 <$> (2,2) (2,True)
(
>$ ) :: Contravariant f => b -> f b -> f abase-prelude BasePrelude.Operators Replace all locations in the output with the same value. The default definition is contramap . const, but this may be overridden with a more efficient version.
(
>$$< ) :: Contravariant f => f b -> (a -> b) -> f abase-prelude BasePrelude.Operators This is an infix version of contramap with the arguments flipped.