Specs

chain(Witchcraft.Chain.t(), Witchcraft.Chain.link()) :: Witchcraft.Chain.t()

Sequentially compose actions, piping values through successive function chains.

The applied linking function must be unary and return data in the same type of container as the input. The chain function essentially "unwraps" a contained value, applies a linking function that returns the initial (wrapped) type, and collects them into a flat(ter) structure.

chain/2 is sometimes called "flat map", since it can also be expressed as data |> map(link_fun) |> flatten().

As a diagram:

%Container<data> --- (data -> %Container<updated_data>) ---> %Container<updated_data>

Examples

iex> chain([1, 2, 3], fn x -> [x, x] end)
[1, 1, 2, 2, 3, 3]

iex> [1, 2, 3]
...> |> chain(fn x -> [x, x] end)
...> |> chain(fn y -> [y, 2 * y, 3 * y] end)
[1, 2, 3, 1, 2, 3, 2, 4, 6, 2, 4, 6, 3, 6, 9, 3, 6, 9]

iex> chain([1, 2, 3], fn x ->
...>   chain([x + 1], fn y ->
...>     chain([y + 2, y + 10], fn z ->
...>       [x, y, z]
...>     end)
...>   end)
...> end)
[1, 2, 4, 1, 2, 12, 2, 3, 5, 2, 3, 13, 3, 4, 6, 3, 4, 14]