Crate gur

Example

use gur::gur::{GurBuilder, Gur};
use gur::action::Action;
use gur::memento::Memento;

#[derive(Clone)]
struct MyState(i32);

impl Memento for MyState {
    type Target = MyState;
    fn to_memento(&self) -> Self::Target {
        self.clone()
    }
    fn from_memento(m: &Self::Target) -> Self {
        m.clone()
    }
}

struct Add(i32);

impl Action for Add {
    type State = MyState;
    fn execute(&self, prev: Self::State) -> Self::State {
        MyState(prev.0 + self.0)
    }
}

fn main() {
    let mut gur = GurBuilder::new().build(MyState(0));

    gur.act(Add(1));
    assert_eq!(1, gur.0);

    gur.undo().unwrap();
    assert_eq!(0, gur.0);

    gur.redo().unwrap();
    assert_eq!(1, gur.0);
}

Modules

action

gur

memento