@spec element(any(), [any()]) :: Reactor.Template.Element.t()

The element template helper for the Reactor DSL.

Example

defmodule ExampleReactor do
  use Reactor

  input :numbers

  map :double_numbers do
    source input(:numbers)

    step :double do
      argument :number, element(:double_numbers)

      run fn args, _ ->
        {:ok, args.number * 2}
      end
    end

    return :double
  end
end

@spec input(atom(), [any()]) :: Reactor.Template.Input.t()

The input template helper for the Reactor DSL.

Example

defmodule ExampleReactor do
  use Reactor

  input :name

  step :greet do
    # here: --------↓↓↓↓↓
    argument :name, input(:name)
    run fn
      %{name: nil}, _, _ -> {:ok, "Hello, World!"}
      %{name: name}, _, _ -> {:ok, "Hello, #{name}!"}
    end
  end
end

Extracting nested values

You can provide a list of keys to extract from a data structure, similar to Kernel.get_in/2 with the condition that the input value is either a struct or implements the Access protocol.

@spec result(atom(), [any()]) :: Reactor.Template.Result.t()

The result template helper for the Reactor DSL.

Example

defmodule ExampleReactor do
  use Reactor

  step :whom do
    run fn _, _ ->
      {:ok, Enum.random(["Marty", "Doc", "Jennifer", "Lorraine", "George", nil])}
    end
  end

  step :greet do
    # here: --------↓↓↓↓↓↓
    argument :name, result(:whom)
    run fn
      %{name: nil}, _, _ -> {:ok, "Hello, World!"}
      %{name: name}, _, _ -> {:ok, "Hello, #{name}!"}
    end
  end
end

Extracting nested values

You can provide a list of keys to extract from a data structure, similar to Kernel.get_in/2 with the condition that the result is either a struct or implements the Access protocol.

@spec value(any()) :: Reactor.Template.Value.t()

The value template helper for the Reactor DSL.

Example

defmodule ExampleReactor do
  use Reactor

  input :number

  step :times_three do
    argument :lhs, input(:number)
    # here: -------↓↓↓↓↓
    argument :rhs, value(3)

    run fn args, _ ->
      {:ok, args.lhs * args.rhs}
    end
  end
end