Crate macro_machines

State machine macros with logging and graphviz dotfile generation

Repository

An example Door state machine with:

• an open_count extended state variable
• two states: Closed (with state-local variable knock_count) and Open
• three events: one internal event Knock (with action on the Closed state) and two external events Open (wth associated action) and Close (without any action)

def_machine_debug! {
  Door (open_count : u64) @ _door {
    STATES [
      state Closed (knock_count : u64)
      state Opened ()
    ]
    EVENTS [
      event Knock <Closed> () { knock_count } => { *knock_count += 1; }
      event Open  <Closed> => <Opened> ()  {} => { *open_count += 1; }
      event Close <Opened> => <Closed> ()
    ]
    initial_state:  Closed {
      initial_action: {
        println!("hello");
        println!("open_count: {:?}", _door.as_ref().open_count);
      }
    }
    terminal_state: Closed {
      terminate_success: {
        println!("open_count: {:?}", _door.as_ref().open_count);
        println!("goodbye")
      }
      terminate_failure: {
        panic!("door was left: {:?}", _door.state())
      }
    }
  }
}

The Door::dotfile() function will generate a dotfile string that can be saved and rendered as a PNG with graphviz dot layout:

$ dot -Tpng door.dot > door.png

Macros

debug	Logs a message at the debug level.
def_machine	State machines with a default initial state.
def_machine_debug	State machines with a default initial state and deriving Debug.
def_machine_nodefault	State machine that requires runtime initialization.
def_machine_nodefault_debug	State machine that requires runtime initialization and deriving Debug.
error	Logs a message at the error level.
info	Logs a message at the info level.
log	The standard logging macro.
trace	Logs a message at the trace level.
warn	Logs a message at the warn level.

Enums

HandleEventException

Describes an exceptional result when attempting to handle an event.

Traits

MachineDotfile

Methods for dotfile creation