Trait Signal 

pub trait Signal: Clone + 'static {
    type Output: 'static;
    type Guard: WatcherGuard;

    // Required methods
    fn get(&self) -> Self::Output;
    fn watch(
        &self,
        watcher: impl Fn(Context<Self::Output>) + 'static,
    ) -> Self::Guard;

    // Provided method
    fn identity(&self) -> Option<SignalIdentity> { ... }
}

The core trait for reactive system.

Types implementing Signal represent a computation that can produce a value and notify observers when that value changes.

Required Associated Types

type Output: 'static

The type of value produced by this computation.

type Guard: WatcherGuard

The guard type returned by the watch method that manages watcher lifecycle.

Required Methods

fn get(&self) -> Self::Output

Execute the computation and return the current value.

fn watch( &self, watcher: impl Fn(Context<Self::Output>) + 'static, ) -> Self::Guard

Register a watcher to be notified when the computed value changes.

Returns a guard that, when dropped, will unregister the watcher.

Provided Methods

fn identity(&self) -> Option<SignalIdentity>

Returns the stable semantic identity of this signal, when one exists.

Constant signals intentionally return None because they do not own observable state.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl Signal for &'static str

type Output = &'static str

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for Cow<'static, str>

type Output = Cow<'static, str>

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for Duration

type Output = Duration

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for String

type Output = String

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for bool

type Output = bool

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for char

type Output = char

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for f32

type Output = f32

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for f64

type Output = f64

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for i8

type Output = i8

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for i16

type Output = i16

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for i32

type Output = i32

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for i64

type Output = i64

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for isize

type Output = isize

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for u8

type Output = u8

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for u16

type Output = u16

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for u32

type Output = u32

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for u64

type Output = u64

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl Signal for usize

type Output = usize

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl<K: Clone + 'static, V: Clone + 'static> Signal for BTreeMap<K, V>

type Output = BTreeMap<K, V>

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl<T, U> Signal for (T, U)

where T: Signal, U: Signal, T::Output: Clone, U::Output: Clone,

type Output = (<T as Signal>::Output, <U as Signal>::Output)

type Guard = (<T as Signal>::Guard, <U as Signal>::Guard)

fn get(&self) -> Self::Output

fn watch( &self, watcher: impl Fn(Context<Self::Output>) + 'static, ) -> Self::Guard

impl<T: 'static> Signal for &'static [T]

type Output = &'static [T]

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl<T: Clone + 'static, const N: usize> Signal for [T; N]

type Output = [T; N]

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl<T: Clone + 'static> Signal for BTreeSet<T>

type Output = BTreeSet<T>

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl<T: Clone + 'static> Signal for Vec<T>

type Output = Vec<T>

type Guard = ()

fn get(&self) -> Self::Output

fn watch(&self, _watcher: impl Fn(Context<Self::Output>) + 'static)

impl<T: Signal, E: Signal> Signal for Result<T, E>

type Output = Result<<T as Signal>::Output, <E as Signal>::Output>

type Guard = Result<<T as Signal>::Guard, <E as Signal>::Guard>

fn get(&self) -> Self::Output

fn identity(&self) -> Option<SignalIdentity>

fn watch( &self, watcher: impl Fn(Context<Self::Output>) + 'static, ) -> Self::Guard

impl<T: Signal> Signal for Option<T>

type Output = Option<<T as Signal>::Output>

type Guard = Option<<T as Signal>::Guard>

fn get(&self) -> Self::Output

fn identity(&self) -> Option<SignalIdentity>

fn watch( &self, watcher: impl Fn(Context<Self::Output>) + 'static, ) -> Self::Guard

Implementors