Rust etsm

Tiny state machine for rust, see etsm

Description

Implement a bare bones state machine in many languages. This library aim to be simple as possible and support only basic features:

• states on object (owner)
• optional enter/exit methods
• virtual state user methods
• is in
• unrestricted transitions
• no runtime allocation

Install

Add the following line to your Cargo.toml file: [dependencies] etsm = "x.y.z" latest version:

Or

Add this file directly into your project: etsm

Examples

Simple

Declare state machine rust use etsm::*; state_machine!( Foo, State { {A, Some(Foo::enter_a), Some(Foo::exit_a)}, {B, Some(Foo::enter_b), None} } );

Instanciate the state machine in your struct ```rust struct Foo { state_machine: StateMachine, }

impl Foo { fn new() -> Foo { Foo { state_machine: StateMachine::new(), } } } ```

Add enter/exit callbacks ```rust impl Foo { //... fn enter_a(&mut self) { print!(" ->A "); }

fn exit_a(&mut self) {
    print!(" A-> ");
}

fn enter_b(&mut self) {
    print!(" ->B ");
}

} ```

Execute transitions rust fn run(&mut self) { transition!(self, state_machine, Some(State::A)); transition!(self, state_machine, Some(State::B)); transition!(self, state_machine, None); }

Output: " ->A A-> ->B "\ Sample simple.rs

Virtual State Methods

Declare state machine with data, you might use any type of data, view this data as static data for each state. rust state_machine!( Foo, Data, State { // state, enter, exit, data { A, None, None, Some(Data { run : Foo::run_a })}, { B, None, None, Some(Data { run : Foo::run_b })} } );

Declare the statedata struct rust struct Data { run: fn(&mut Foo), }

Implement Foo ```rust struct Foo { state_machine: StateMachine, }

impl Foo { fn new() -> Foo { Foo { state_machine: StateMachine::new(), } }

fn run_a(&mut self) {
    print!(" A ");
}

fn run_b(&mut self) {
    print!(" B ");
}

fn run(&mut self) {
    // call run on the current state
    if let Some(statedata) = get_statedata(&self.state_machine) {
        (statedata.run)(self);
    }
}

} ```

Call method run on Foo that forward it to the current state ```rust

[test]

fn virtual_call() { let mut foo = Foo::new();

transition!(&mut foo, state_machine, Some(State::A));
foo.run();

transition!(&mut foo, state_machine, Some(State::B));
foo.run();

} ``` Output: " A B "\ Sample virtual_call.rs