Struct Binding 

pub struct Binding<T: 'static> {
    pub read: ReadSignal<T>,
    /* private fields */
}

A reactive, two-way binding to one field-shaped value.

Interaction boundaries

Binding::commit and Binding::focus_exit report independent facts:

• Commit is the widget-defined end of one interaction unit. A switch click or slider release can commit while the control remains focused.
• Focus Exit means focus left the widget’s complete logical focus scope. An unchanged native text input can report Focus Exit without committing a value change.

Native control example

A switch click can call write, then commit, while focus remains on the switch. A later departure from the switch calls focus_exit. An unchanged text input that loses focus can call only focus_exit because there was no value interaction to commit.

Compound-widget example

For a compound widget, the logical focus scope includes its owned controls and popup or portal content. Moving focus from a combobox trigger into its popup does not report Focus Exit. When a selection writes and commits before focus leaves that complete scope, report the write, then Commit, then Focus Exit.

Equality compares the binding’s producer-defined identity. Equal bindings are guaranteed to represent interchangeable read, write, Commit, and Focus Exit behavior; producers may conservatively return unequal bindings when they cannot prove that interchangeability.

Fields

read: ReadSignal<T>

The binding’s reactive value.

Implementations

impl<T: 'static> Binding<T>

pub fn new( read: ReadSignal<T>, write: Callback<(T, ChangeOrigin)>, commit: Callback<()>, ) -> Self

Creates a binding identified by its exact read, write, and commit handles.

Focus Exit is a no-op unless replaced with Binding::with_focus_exit or Binding::with_focus_exit_using_identity.

pub fn new_with_identity<I>( read: ReadSignal<T>, write: Callback<(T, ChangeOrigin)>, commit: Callback<()>, identity: I, ) -> Self

where I: PartialEq + 'static,

Creates a binding with a producer-defined comparable identity.

Equal identities must always represent interchangeable read, write, and commit behavior. This constructor installs no-op Focus Exit behavior, so that behavior is interchangeable as well. Producers that cannot prove interchangeability should use Binding::new instead.

pub fn with_focus_exit(self, focus_exit: Callback<()>) -> Self

Adds the callback invoked when focus leaves the widget’s complete logical focus scope.

This builder also incorporates the callback into binding identity, preserving the guarantee that equal bindings have interchangeable Focus Exit behavior. It does not alter Commit or imply any form-library blur, touched, or validation semantics.

pub fn with_focus_exit_using_identity(self, focus_exit: Callback<()>) -> Self

Adds Focus Exit behavior covered by the binding’s existing comparable identity.

Unlike Binding::with_focus_exit, this builder does not incorporate the callback’s allocation identity. Calling it asserts that bindings with equal existing identities also have interchangeable Focus Exit behavior, in addition to interchangeable read, write, and Commit behavior. Producers that cannot prove this must use Binding::with_focus_exit instead.

This builder does not alter Commit or imply any form-library blur, touched, or validation semantics.

pub fn write(&self, value: T, origin: ChangeOrigin)

Writes a value and preserves where the change originated.

pub fn commit(&self)

Reports the widget-defined end of one interaction unit.

pub fn focus_exit(&self)

Reports that focus left the widget’s complete logical focus scope.

This is independent from Binding::commit. Widgets are responsible for defining their complete scope, including owned child controls and popup or portal content, and for suppressing reports while focus moves within it.

pub fn into_trio(self) -> BindingPropTrio<T>

Decomposes this binding into the dependency-free widget prop contract.

The lower-level on_change callback has no origin parameter, so its writes are user writes.

Trait Implementations

impl<T: 'static> Clone for Binding<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug + 'static> Debug for Binding<T>

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

Formats the value using the given formatter.

impl<T: 'static> From<(ReadSignal<T>, Callback<T>)> for Binding<T>

fn from((read, on_change): (ReadSignal<T>, Callback<T>)) -> Self

Converts to this type from the input type.

impl<T: 'static> From<Binding<T>> for BindingPropTrio<T>

fn from(binding: Binding<T>) -> Self

Converts to this type from the input type.

impl<T: 'static> From<Binding<T>> for FieldContext

fn from(binding: Binding<T>) -> Self

Converts to this type from the input type.

impl<T: 'static> From<Signal<T>> for Binding<T>

fn from(signal: Signal<T>) -> Self

Converts to this type from the input type.

impl<T: 'static> From<T> for Binding<T>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T: 'static> PartialEq for Binding<T>

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.