Trait actions::Component[−][src]

pub trait Component<Error: stdError + 'static = ActionsError> {
    type Action: Clone;
    fn apply(
        &mut self, 
        action: &Self::Action
    ) -> Result<Option<Self::Action>, Error>;
}

Component is a trait that should be implemented for any datatype that describes the state of your application.

Associated Types

`type Action: Clone`

The type of the action. The action could be of any type but using an enum is encouraged.

Required Methods

`fn apply( &mut self, action: &Self::Action ) -> Result<Option<Self::Action>, Error>`

Apply an action and return the inverse of that action.

Arguments

action - Data that describes an action.

Example

extern crate actions;
use actions::Component;
use actions::Error;
 
#[derive(Clone)]
struct Counter {
    counter: i32
}

#[derive(Clone)]
enum CounterAction {
    Increment,
    Decrement,
}

impl Component for Counter {
    type Action = CounterAction;

    fn apply(&mut self, action: &Self::Action)->Result<Option<Self::Action>,Error>
    {
        let inverse = match action {
            CounterAction::Increment => {
                self.counter += 1;
                Some(CounterAction::Decrement)
            },
            CounterAction::Decrement => {
                self.counter -= 1;
                Some(CounterAction::Increment)
            }
        };
        Ok(inverse)
    }
}