A FunctionK transforms values from one first-order-kinded type (a type that takes a single type parameter,
such as List or Option) into another first-order-kinded type.
This transformation is universal, meaning that a FunctionK[List, Option] will translate all List[A] values into an Option[A]
value for all possible types of A. This explanation may be easier to understand if we first step back and talk about ordinary functions.
A FunctionK transforms values from one first-order-kinded type (a type that takes a single type parameter, such as List or Option) into another first-order-kinded type. This transformation is universal, meaning that a FunctionK[List, Option] will translate all List[A] values into an Option[A] value for all possible types of A. This explanation may be easier to understand if we first step back and talk about ordinary functions.
- incoming effect
- result effect
0.5.5
- https://typelevel.org/cats/datatypes/functionk.html