A GenServer wrapper around Statifier.StateChart for asynchronous state chart processing.

Using the StateMachine Macro

The use Statifier.StateMachine macro provides a convenient way to create StateMachine modules with callback support:

defmodule MyMachine do
  use Statifier.StateMachine, scxml: "my_machine.xml"

  def handle_state_enter(state_id, state_chart, _context) do
    Logger.info("Entered: #{state_id}")
  end

  def handle_send_action(target, event, data, _state_chart) do
    case target do
      "external_api" -> MyAPI.send(event, data)
      _ -> :ok
    end
  end
end

Macro Options

• :scxml - SCXML file path or XML string (required)
• :name - GenServer registration name
• :snapshot_interval - Milliseconds between snapshot calls
• :invoke_handlers - Map of invoke type to handler function for <invoke> elements

Manual Usage (without macro)

You can also use StateMachine directly without the macro:

Provides an OTP-compliant interface for running state charts as processes, with proper supervision support and clean separation from synchronous operations.

Usage

# Start from SCXML file
{:ok, pid} = Statifier.StateMachine.start_link("path/to/machine.xml")

# Start from SCXML string
{:ok, pid} = Statifier.StateMachine.start_link(xml_string)

# Send events asynchronously
Statifier.send(pid, "start_event")
Statifier.send(pid, "data_event", %{key: "value"})

# Query current state
active_states = Statifier.StateMachine.active_states(pid)

Comparison with Synchronous API

StateMachine provides asynchronous processing via GenServer:

• Statifier.send(pid, event) - Asynchronous, fire-and-forget
• Statifier.StateMachine.active_states(pid) - Synchronous query

For synchronous processing, use the existing direct API:

• Statifier.send_sync(state_chart, event) - Returns updated state chart
• Statifier.Configuration.active_leaf_states(config) - Direct access