. package:base

(.) :: (b -> c) -> (a -> b) -> a -> c
base Prelude Data.Function GHC.Base
Right to left function composition. 
(f . g) x = f (g x)

f . id = f = id . f

Examples

>>> map ((*2) . length) [[], [0, 1, 2], [0]]
[0,6,2]

>>> foldr (.) id [(+1), (*3), (^3)] 2
25

>>> let (...) = (.).(.) in ((*2)...(+)) 5 10
30
(.) :: forall (b :: k) (c :: k) (a :: k) . Category cat => cat b c -> cat a b -> cat a c
base Control.Category
Morphism composition. Implementations should satisfy the law:
  • Associativity f . (g . h) = (f . g) . h
This means that the way morphisms are grouped is irrelevant, so it is unambiguous to write a composition of morphisms as f . g . h, without parentheses.
(.&.) :: Bits a => a -> a -> a
base Data.Bits GHC.Bits
Bitwise "and"
(.<<.) :: Bits a => a -> Int -> a
base Data.Bits
Infix version of shiftL.
(.>>.) :: Bits a => a -> Int -> a
base Data.Bits
Infix version of shiftR.
(.^.) :: Bits a => a -> a -> a
base Data.Bits
Infix version of xor.
(.|.) :: Bits a => a -> a -> a
base Data.Bits GHC.Bits
Bitwise "or"
(!<<.) :: Bits a => a -> Int -> a
base Data.Bits
Infix version of unsafeShiftL.
(!>>.) :: Bits a => a -> Int -> a
base Data.Bits
Infix version of unsafeShiftR.
newtype ((f :: k2 -> Type) :.: (g :: k1 -> k2)) (p :: k1)
base GHC.Generics
Composition of functors