View Source Witchcraft.Functor (Witchcraft v1.0.6-doma)
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
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
@type t() :: any()
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
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]"}
async_map/2
with arguments flipped.
examples
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
The same as async_map/2
, except with the mapping function curried
examples
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
map
a function over a data structure, with each mapping occuring asynchronously.
Especially helpful when each application take a long time.
examples
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
async_lift/2
with arguments flipped.
examples
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
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
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
Examples
iex> fn x -> x + 1 end |> over([1, 2, 3])
[2, 3, 4]
Replace all inner elements with a constant value
examples
Examples
iex> replace([1, 2, 3], "hi")
["hi", "hi", "hi"]
Operator alias for lift/2
example
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