Data.Index

Index, necessary instances for it, end and mid for any container

Documentation

newtype Index t i

This type can contain any container-independent values to be indexed with

Constructors

Index

Fields

• runIndex :: forall a. t a -> i

Instances

Monad (Index t)

Reader-like Monad instance

Methods

(>>=) :: Index t a -> (a -> Index t b) -> Index t b

(>>) :: Index t a -> Index t b -> Index t b

return :: a -> Index t a

fail :: String -> Index t a

Functor (Index t)

Reader-like Functor instance

Methods

fmap :: (a -> b) -> Index t a -> Index t b

(<$) :: a -> Index t b -> Index t a

Applicative (Index t)

Reader-like Applicative instance

Methods

pure :: a -> Index t a

(<*>) :: Index t (a -> b) -> Index t a -> Index t b

liftA2 :: (a -> b -> c) -> Index t a -> Index t b -> Index t c

(*>) :: Index t a -> Index t b -> Index t b

(<*) :: Index t a -> Index t b -> Index t a

Num i => Num (Index t i)

Num instance is done via liftA2 and pure

Methods

(+) :: Index t i -> Index t i -> Index t i

(-) :: Index t i -> Index t i -> Index t i

(*) :: Index t i -> Index t i -> Index t i

negate :: Index t i -> Index t i

abs :: Index t i -> Index t i

signum :: Index t i -> Index t i

fromInteger :: Integer -> Index t i

run :: t a -> Index t i -> i

Flipped version of runIndex

end :: Foldable t => Index t Int

The end of any linear container

mid :: Foldable t => Index t Int

The middle of any linear container