FsmDiagram

FsmDiagram is a State Machine Control library to embed sequences of operations.

Feature

• This is not to change or control the state, rather to do sequential operations.
• Sequential steps are implemented by calling state function.
• Transits states mostly by message events to receive inside.

Usage

it starts according to fsm_start() to activate state machine task.

Sample state diagram:

stateDiagram-v2
[*] --> init()
init() --> ledoff() 
ledoff() --> ledon() : on
ledon() --> ledoff() : off

Sample codes:

defmodule FsmSample1 do
  @moduledoc """
  Sample of FsmDiagram for test
  """
  use FsmDiagram

  def start_link(fsm_id \\ __MODULE__) do
    {:ok, _pid} = fsm_start(fsm_id, :init, self())
  end

  def init(pid) do
    # initialize process
    send(pid, {:initialized, self(), "finishied init()"})
    moveto(:ledoff, [])
  end

  def ledoff(argv) do
    # turn off led
    _ledoff(argv)
  end
  defp _ledoff(argv) do
    receive do
      {:on, _from, _msg}  -> moveto(:ledon, [0])
      _ -> _ledoff(argv)
    end
  end

  def ledon(argv) do
    # turn on led
    _ledon(argv)
  end
  defp _ledon(argv) do
    receive do
      {:off, _from, _msg} -> moveto(:ledoff, [0])
      _    -> _ledon(argv)
    end
  end
  
  defp moveto(func, argv) do
    func = Function.capture(__MODULE__, func, 1)
    update_fnc(func, argv)
  end
end

Each state function will be called by the task fsm_start() kickoff Task.start_link(). You need to prepare moveto(func, argv) which set next state function and the argv into FsmDiagram. Then FsmDiagram callbacks next state function when current function returns. fnc should be added with Module(&Module.fnc/1) to allow the different module.

installing

def deps do
  [
    {:fsm_diagram, "~> 0.1.0"}
  ]
end