com.mojang.datafixers.kinds

Interface Traversable<T extends K1,Mu extends Traversable _>

Type Parameters:

T - The container type.

Mu - The witness type for this traversable.

All Superinterfaces:

Mu<T>, Functor T, Kind1 T

All Known Subinterfaces:

CartesianLike<T,C,Mu>, CocartesianLike<T,C,Mu>

All Known Implementing Classes:

Either.Instance, ListBox.Instance, OptionalBox.Instance, Pair.Instance

public interface Traversable<T extends K1,Mu extends Traversable _>
extends Functor T

The traversable type class for some container type takes in an effectful transformation and produces an equivalent effectful transformation on the container type.

This type class may be used to e.g. produce a function ListBox<A> -> DataResult<ListBox<B>> from a function A -> DataResult<B>, only producing a successful result if all the original elements were converted successfully.

Note that the implementation of Functor.map(Function, App) inherited from Functor can be implemented in terms of traverse(Applicative, Function, App) as map(f, ta) = traverse(IdF, f, ta). This interface leaves that method abstract because of the differing function types in Functor.map(Function, App) and traverse(Applicative, Function, App) that make the default implementation outline above impossible without an unchecked (albeit safe) cast.

Type Shape:

%.Type. %0

See Also:

Applicative

Method Summary

Modifier and Type	Method and Description
default <F extends K1,A> F<T<A>>	flip(Applicative F applicative, T<F<A>> input) Swaps the order of this container with a nested container in input.
<F extends K1,A,B> F<T<B>>	traverse(Applicative F applicative, (A) -> F<B> function, T<A> input) Applies a function that produces an Applicative effect to each value contained within input, then builds a container with an equivalent structure containing the (unboxed) results.

Methods inherited from interface com.mojang.datafixers.kinds.Functor

map

Methods inherited from interface com.mojang.datafixers.kinds.Kind1

group, group, group, group, group, group, group, group, group, group, group, group, group, group, group, group

Method Detail

traverse

<F extends K1,A,B> F<T<B>> traverse(Applicative F applicative,
                                    (A) -> F<B> function,
                                    T<A> input)

Applies a function that produces an Applicative effect to each value contained within input, then builds a container with an equivalent structure containing the (unboxed) results.

API Note:

This function defines the traversable operator with the applicative functor F.

Type Parameters:

F - The type of the effect.

A - The input type.

B - The output type.

Parameters:

applicative - An instance of the Applicative type class which defines the behavior of F.

function - The function to apply.

input - The input container.

Returns:

A container holding the results of applying function to each element, if the function was successful for every element.

flip

default <F extends K1,A> F<T<A>> flip(Applicative F applicative,
                                      T<F<A>> input)

Swaps the order of this container with a nested container in input.

This function is equivalent to

 traverse(applicative, Function.identity(), input)

Type Parameters:

F - The nested container type.

A - The contained type.

Parameters:

applicative - An instance of the Applicative type class which defines the behavior of F.

input - The input container.

Returns:

The nested contained value with the containers swapped.

See Also:

traverse(Applicative, Function, App)