Witchcraft v1.0.0 Witchcraft.Functor View Source

Functors are datatypes that allow the application of functions to their interior values. Always returns data in the same structure (same size, tree layout, and so on).

Please note that bitstrings are not functors, as they fail the functor composition constraint. They change the structure of the underlying data, and thus composed lifting does not equal lifing a composed function. If you need to map over a bitstring, convert it to and from a charlist.

Type Class

An instance of Witchcraft.Functor must define Witchcraft.Functor.map/2.

Functor  [map/2]

Link to this section Summary

Functions

<~/2 with arguments flipped

map with its arguments flipped

async_map/2 with arguments flipped

The same as async_map/2, except with the mapping function curried

map a function over a data structure, with each mapping occuring asynchronously

async_lift/2 with arguments flipped

map/2 but with the function automatically curried

map a function into one layer of a data wrapper. There is an autocurrying variant: lift/2

lift/2 but with arguments flipped

Replace all inner elements with a constant value

Operator alias for lift/2

Link to this section Types

Link to this section Functions

<~/2 with arguments flipped.

iex> (fn x -> x + 5 end) <~ [1,2,3]
[6, 7, 8]

Note that the mnemonic is flipped from |>, and combinging directions can be confusing. It’s generally recommended to use ~>, or to keep <~ on the same line both of it’s arguments:

iex> fn(x, y) -> x + y end <~ [1, 2, 3]
...> |> List.first()
...> |> apply([9])
10

…or in an expression that’s only pointing left:

iex> fn y -> y * 10 end
...> <~ fn x -> x + 55 end
...> <~ [1, 2, 3]
[560, 570, 580]

map with its arguments flipped.

Examples

iex> across(fn x -> x + 1 end, [1, 2, 3])
[2, 3, 4]

iex> fn
...>   int when is_integer(int) -> int * 100
...>   value -> inspect(value)
...> end
...> |> across(%{a: 2, b: [1, 2, 3]})
%{a: 200, b: "[1, 2, 3]"}
Link to this function async_across(fun, functor) View Source
async_across((any -> any), Witchcraft.Functor.t) :: Witchcraft.Functor.t

async_map/2 with arguments flipped.

Examples

iex> fn x -> x * 10 end
...> |> async_across([1, 2, 3])
[10, 20, 30]

fn x ->
  Process.sleep(500)
  x * 10
end
|> async_across(Enumto_list(0..10_000))
#=> [0, 10, ...] in around a second
Link to this function async_lift(functor, fun) View Source
async_lift(Witchcraft.Functor.t, (... -> any)) :: Witchcraft.Functor.t

The same as async_map/2, except with the mapping function curried

Examples

iex> async_lift([1, 2, 3], fn x -> x * 10 end)
[10, 20, 30]

0..10_000
|> Enum.to_list()
|> async_lift(fn x ->
  Process.sleep(500)
  x * 10
end)
#=> [0, 10, ...] in around a second
Link to this function async_map(functor, fun) View Source
async_map(Witchcraft.Functor.t, (any -> any)) :: Witchcraft.Functor.t

map a function over a data structure, with each mapping occuring asynchronously.

Especially helpful when each application take a long time.

Examples

iex> async_map([1, 2, 3], fn x -> x * 10 end)
[10, 20, 30]

0..10_000
|> Enum.to_list()
|> async_map(fn x ->
  Process.sleep(500)
  x * 10
end)
#=> [0, 10, ...] in around a second
Link to this function async_over(fun, functor) View Source
async_over((... -> any), Witchcraft.Functor.t) :: Witchcraft.Functor.t

async_lift/2 with arguments flipped.

Examples

iex> fn x -> x * 10 end
...> |> async_over([1, 2, 3])
[10, 20, 30]

fn x ->
  Process.sleep(500)
  x * 10
end
|> async_over(Enumto_list(0..10_000))
#=> [0, 10, ...] in around a second

map/2 but with the function automatically curried

Examples

iex> lift([1, 2, 3], fn x -> x + 1 end)
[2, 3, 4]

iex> [1, 2, 3]
...> |> lift(fn x -> x + 55 end)
...> |> lift(fn y -> y * 10 end)
[560, 570, 580]

iex> [1, 2, 3]
...> |> lift(fn(x, y) -> x + y end)
...> |> List.first()
...> |> apply([9])
10

map a function into one layer of a data wrapper. There is an autocurrying variant: lift/2.

Examples

iex> map([1, 2, 3], fn x -> x + 1 end)
[2, 3, 4]

iex> %{a: 1, b: 2} ~> fn x -> x * 10 end
%{a: 10, b: 20}

iex> map(%{a: 2, b: [1, 2, 3]}, fn
...>   int when is_integer(int) -> int * 100
...>   value -> inspect(value)
...> end)
%{a: 200, b: "[1, 2, 3]"}

lift/2 but with arguments flipped.

Examples

iex> fn x -> x + 1 end |> over([1, 2, 3])
[2, 3, 4]

Replace all inner elements with a constant value

Examples

iex> replace([1, 2, 3], "hi")
["hi", "hi", "hi"]

Operator alias for lift/2

Example

iex> [1, 2, 3]
...> ~> fn x -> x + 55 end
...> ~> fn y -> y * 10 end
[560, 570, 580]

iex> [1, 2, 3]
...> ~> fn(x, y) -> x + y end
...> |> List.first()
...> |> apply([9])
10