macro-machines

State machine macros with logging and graphviz dotfile generation

Documentation

Usage

The macros provided by this library expand to definitions using const fns and some intrinsics to help generate dotfiles, so these features must be enabled in the crate root:

#![feature(const_fn)]
#![feature(core_intrinsics)]

#[macro_use] extern crate macro_machines;

Define and use a minimal state machine:

def_machine_debug!{
  machine M {
    STATES [
      state S ()
      state T ()
    ]
    EVENTS [
      event A <S> => <T> ()
    ]
    EXTENDED []
    initial_state: S
  }
}

fn main () {
  use macro_machines::HandleEventException;

  let mut m = M::initial();
  let e = Event::from_id (EventId::A);
  m.handle_event (e).unwrap();
  let e = Event::from_id (EventId::A);
  assert_eq!(m.handle_event (e), Err (HandleEventException::WrongState));
}

Generate a dotfile and write to file:

  use std::io::Write;
  use macro_machines::MachineDotfile;
  let mut f = std::fs::File::create ("minimal.dot").unwrap();
  f.write_all (M::dotfile().as_bytes()).unwrap();
  drop (f);

Rendered as PNG with $ dot -Tpng minimal.dot > minimal.png:

For examples of more complex state machines, see the ./examples/ directory.

Dependencies