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  1. (<$) :: Functor f => a -> f b -> f a

    base-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
    

  2. (<$>) :: Functor f => (a -> b) -> f a -> f b

    base-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)
    

  3. (>$) :: Contravariant f => b -> f b -> f a

    base-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.

  4. (>$$<) :: Contravariant f => f b -> (a -> b) -> f a

    base-prelude BasePrelude.Operators

    This is an infix version of contramap with the arguments flipped.

  5. (>$<) :: Contravariant f => (a -> b) -> f b -> f a

    base-prelude BasePrelude.Operators

    This is an infix alias for contramap.

  6. (</$>) :: Functor f => (DirTree a -> DirTree b) -> f (AnchoredDirTree a) -> f (AnchoredDirTree b)

    directory-tree System.Directory.Tree

    Allows for a function on a bare DirTree to be applied to an AnchoredDirTree within a Functor. Very similar to and useful in combination with <$>:

  7. (<$) :: Functor f => a -> f b -> f a

    mixed-types-num Numeric.MixedTypes.PreludeHiding

    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
    

  8. (<$>) :: Functor f => (a -> b) -> f a -> f b

    mixed-types-num Numeric.MixedTypes.PreludeHiding

    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)
    

  9. (<$>) :: Functor g => (forall (a :: k) . () => p a -> q a) -> g p -> g q

    rank2classes Rank2

    No documentation available.

  10. (&!$*) :: forall (tag :: Symbol) m t . (Sayable tag m, Foldable t) => (Doc SayableAnn -> Doc SayableAnn) -> t m -> Saying tag

    sayable Text.Sayable

    A helper operator that applies the first argument (a Prettyprinter adaptation function) to the result of a Foldable collection of Sayable items. This is essentially a combination of the &! and &* operators where the first operation is applied to the entire list, rather than each element of the list (as with &!*).

    >>> sez @"info" $ t'"three:" &- PP.align &!$* [1, 2, 3::Int]
    "three: 1, 2, 3"
    
    As with the &!* operator (and unlike the &* operator), a null collection is passed to the converter first argument. @since: 1.1.0.0

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