Data.Lens.Injection.Injection8

The eighth injection of a sum type, as a prism. The sum-type dual of Control.Lens.Field8.

Synopsis

classclass Injection8 s t a b | s -> a, t -> b, s b -> t, t a -> s where

Access the eighth constructor of a sum type.

Where Control.Lens._8 is the eighth projection out of a product, _I8 is the eighth injection into a sum.

The default implementation is the prism to the eighth constructor of a Generic type, injection (Proxy :: Proxy 7).

Example3 expressions

>>> data T = C1 | C2 | C3 | C4 | C5 | C6 | C7 | C8 Int | C9 deriving (Show, Generic)>>> instance Injection8 T T Int Int>>> C8 1 ^? _I8Just 1

Example1 expression

>>> C9 ^? _I8Nothing

Example1 expression

>>> _I8 # 1 :: TC8 1