Functor f => f (a -> b) -> a -> f b

fmap :: Functor f => (a -> b) -> f a -> f b
base Prelude, base Data.Functor, base Control.Monad, base Control.Monad.Instances
(<$>) :: Functor f => (a -> b) -> f a -> f b
base Data.Functor, base Control.Applicative
An infix synonym for fmap.
(<*>) :: Applicative f => f (a -> b) -> f a -> f b
base Control.Applicative
ap :: Monad m => m (a -> b) -> m a -> m b
base Control.Monad
In many situations, the liftM operations can be replaced by uses of ap, which promotes function application. > return f `ap` x1 `ap` ... `ap` xn is equivalent to > liftMn f x1 x2 ... xn
(<**>) :: Applicative f => f a -> f (a -> b) -> f b
base Control.Applicative
A variant of <*> with the arguments reversed.
($) :: (a -> b) -> a -> b
base Prelude, base Data.Function
Application operator. This operator is redundant, since ordinary application (f x) means the same as (f $ x). However, $ has low, right-associative binding precedence, so it sometimes allows parentheses to be omitted; for example: > f $ g $ h x = f (g (h x)) It is also useful in higher-order situations, such as map ($ 0) xs, or Data.List.zipWith ($) fs xs.
($!) :: (a -> b) -> a -> b
base Prelude
Strict (call-by-value) application, defined in terms of seq.
fmapDefault :: Traversable t => (a -> b) -> t a -> t b
base Data.Traversable
This function may be used as a value for fmap in a Functor instance.
liftA :: Applicative f => (a -> b) -> f a -> f b
base Control.Applicative
Lift a function to actions. This function may be used as a value for fmap in a Functor instance.
liftM :: Monad m => (a1 -> r) -> m a1 -> m r
base Control.Monad
Promote a function to a monad.
($|) :: (a -> b) -> Strategy a -> a -> b
parallel Control.Parallel.Strategies
Sequential function application. The argument is evaluated using the given strategy before it is given to the function.
($||) :: (a -> b) -> Strategy a -> a -> b
parallel Control.Parallel.Strategies
Parallel function application. The argument is evaluated using the given strategy, in parallel with the function application.
($!!) :: NFData a => (a -> b) -> a -> b
deepseq Control.DeepSeq
the deep analogue of $!. In the expression f $!! x, x is fully evaluated before the function f is applied to it.
map :: (a -> b) -> [a] -> [b]
base Prelude, base Data.List
map f xs is the list obtained by applying f to each element of xs, i.e., > map f [x1, x2, ..., xn] == [f x1, f x2, ..., f xn] > map f [x1, x2, ...] == [f x1, f x2, ...]
mapMonotonic :: (a -> b) -> Set a -> Set b
containers Data.Set
O(n). The mapMonotonic f s == map f s, but works only when f is monotonic. The precondition is not checked. Semi-formally, we have: > and [x < y ==> f x < f y | x <- ls, y <- ls] > ==> mapMonotonic f s == map f s >  
map :: (a -> b) -> IntMap a -> IntMap b
containers Data.IntMap.Strict, containers Data.IntMap.Lazy
O(n). Map a function over all values in the map. > map (++ "x") (fromList [(5,"a"), (3,"b")]) == fromList [(3, "bx"), (5, "ax")]
everywhere :: (forall a. Data a => a -> a) -> (forall a. Data a => a -> a)
syb Data.Generics.Schemes
Apply a transformation everywhere in bottom-up manner
everywhere' :: (forall a. Data a => a -> a) -> (forall a. Data a => a -> a)
syb Data.Generics.Schemes
Apply a transformation everywhere in top-down manner
iterate :: (a -> a) -> a -> [a]
base Prelude, base Data.List
iterate f x returns an infinite list of repeated applications of f to x: > iterate f x == [x, f x, f (f x), ...]
maybe :: b -> (a -> b) -> Maybe a -> b
base Prelude, base Data.Maybe
The maybe function takes a default value, a function, and a Maybe value. If the Maybe value is Nothing, the function returns the default value. Otherwise, it applies the function to the value inside the Just and returns the result.

Show more results