# `macro-machines`
> State machine macros with logging and graphviz dotfile generation
[Documentation](https://spearman.github.io/macro-machines/macro_machines/)
## Usage
The macros provided by this library expand to definitions using `const fn`s and
some intrinsics to help generate dotfiles, so these features must be enabled in
the crate root:
```rust
#![feature(const_fn)]
#![feature(core_intrinsics)]
#[macro_use] extern crate macro_machines;
```
Define and use a minimal state machine:
```rust
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:
```rust
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.
