Trait Binding 

pub trait Binding<T>: Clone + 'static
where
    T: 'static,
{
    // Required methods
    fn read(&self) -> T;
    fn peek(&self) -> T;
    fn write(&self, v: T);

    // Provided methods
    fn write_preview(&self, v: T) { ... }
    fn write_commit(&self, v: T) { ... }
    fn write_teardown(&self, v: T) { ... }
}

A readable-writable value a control can bind to two-way: a Signal, or any projection that knows how to read and write its own slot (day-model’s Field is the other implementor).

The trait lives here rather than in day-pieces so a store crate can implement it without depending on the piece vocabulary; day-pieces re-exports it, so piece code sees no move.

Required Methods

fn read(&self) -> T

Tracked read: the current value, subscribing the running computation to changes.

fn peek(&self) -> T

Untracked read: the current value, subscribing nothing (the reactive world’s “peek”).

fn write(&self, v: T)

Write the value, waking whatever tracks it.

Provided Methods

fn write_preview(&self, v: T)

A live write mid-gesture (Event::ValueChanged): readers must follow, but nothing durable should key off it. Defaults to Binding::write: a plain signal has no notion of “durable”, and a degraded backend that never commits stays correct.

fn write_commit(&self, v: T)

The settled value that ends a gesture (Event::ValueCommitted). Defaults to Binding::write; a day-model field seals its preview session here: one change record, one undo unit, one UPDATE for the whole drag.

fn write_teardown(&self, v: T)

Seal the last preview when its control is disposed. Persistent bindings default to committing; scope-owned signals have already received the preview and may be gone.

Dyn Compatibility

This trait is not dyn compatible.

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

Implementors

impl<F, V, U> Binding<U> for Mapped<F, V, U>

where F: Source<V>, V: Clone + Default + 'static, U: Clone + 'static,

The missing case converts the stored type’s default rather than requiring the UI type to have one: a Color has no Default, and asking every converted type for one would be a tax paid by every caller for a case only a deleted row reaches.

impl<M> Binding<f64> for Numeric<M>

where M: Binding<usize> + Copy + 'static,

impl<S, T, V> Binding<V> for Field<S, T, V>

where S: Source<T>, T: 'static, V: Clone + Default + 'static,

A field is a two-way binding: every control takes one, unchanged.

impl<T> Binding<T> for AnyBinding<T>

where T: 'static,

impl<T> Binding<T> for Signal<T>

where T: Clone + 'static,