Struct reducer::Store

pub struct Store<R, S: Reactor<R>> { /* fields omitted */ }

A reactive state container.

The only way to mutate the internal state managed by Store is by dispatching actions on it. The associated reactor is notified upon every state transition.

Example

use reducer::*;
use std::error::Error;
use std::io::{self, Write};

// The state of your app.
struct Calculator(i32);

// Actions the user can trigger.
struct Add(i32);
struct Sub(i32);
struct Mul(i32);
struct Div(i32);

impl Reducer<Add> for Calculator {
    fn reduce(&mut self, Add(x): Add) {
        self.0 += x;
    }
}

impl Reducer<Sub> for Calculator {
    fn reduce(&mut self, Sub(x): Sub) {
        self.0 -= x;
    }
}

impl Reducer<Mul> for Calculator {
    fn reduce(&mut self, Mul(x): Mul) {
        self.0 *= x;
    }
}

impl Reducer<Div> for Calculator {
    fn reduce(&mut self, Div(x): Div) {
        self.0 /= x;
    }
}

// The user interface.
struct Display;

impl Reactor<Calculator> for Display {
    type Output = io::Result<()>;
    fn react(&self, state: &Calculator) -> Self::Output {
        io::stdout().write_fmt(format_args!("{}\n", state.0))
    }
}

fn main() -> Result<(), Box<dyn Error>> {
    let mut store = Store::new(Calculator(0), Display);

    store.dispatch(Add(5))?; // displays "5"
    store.dispatch(Mul(3))?; // displays "15"
    store.dispatch(Sub(1))?; // displays "14"
    store.dispatch(Div(7))?; // displays "2"

    Ok(())
}

Methods

impl<R, S: Reactor<R>> Store<R, S>

pub fn new(state: R, reactor: S) -> Self

Constructs the Store given the initial state and a reactor.

pub fn subscribe(
    &mut self,
    reactor: impl Into<S>
) -> S

Replaces the reactor and returns the previous one.

Trait Implementations

impl<A, R, S> Dispatcher<A> for Store<R, S> where
    R: Reducer<A>,
    S: Reactor<R>, 

type Output = S::Output

fn dispatch(&mut self, action: A) -> S::Output

Updates the state via <R as Reducer<A>>::reduce and notifies the reactor, returning the result of calling <S as Reactor<R>>::react with a reference to the new state.

impl<R: Eq, S: Eq + Reactor<R>> Eq for Store<R, S>

impl<R: Clone, S: Clone + Reactor<R>> Clone for Store<R, S>

fn clone(&self) -> Store<R, S>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<R: Copy, S: Copy + Reactor<R>> Copy for Store<R, S>

impl<R: PartialEq, S: PartialEq + Reactor<R>> PartialEq<Store<R, S>> for Store<R, S>

fn eq(&self, other: &Store<R, S>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Store<R, S>) -> bool

This method tests for !=.

impl<R: Default, S: Default + Reactor<R>> Default for Store<R, S>

fn default() -> Store<R, S>

Returns the "default value" for a type.

impl<R: Hash, S: Hash + Reactor<R>> Hash for Store<R, S>

fn hash<__HRS: Hasher>(&self, state: &mut __HRS)

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given [Hasher].

impl<R: Debug, S: Debug + Reactor<R>> Debug for Store<R, S>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.