Struct NodeState 

pub struct NodeState { /* private fields */ }

The state every expression node has: its place in the binding path, its source and its current value.

Implementations

impl NodeState

pub fn new() -> Self

pub fn locating_an_element() -> Self

The state of a node whose value is an element it locates from the target of the binding: an element of a name scope, an ancestor, the templated parent.

Such a node holds its value weakly (DEVIATIONS.md, Bindings). The element it finds is kept alive by the tree it was found in, and that tree most often owns the target of the binding, which owns the binding and its nodes: held strongly, as the managed original holds the value of every node, the element and the target keep each other alive. The value reads null once the element is gone.

pub fn index(&self) -> usize

The index of the node in the binding path.

pub fn owner(&self) -> Option<Rc<BindingExpression>>

The owning binding expression.

pub fn source(&self) -> Option<BoxedValue>

The source object from which the node reads its value.

pub fn source_object(&self) -> Option<Ref<FerroObject>>

The source viewed as an object of the class hierarchy.

pub fn value(&self) -> Option<BoxedValue>

The current value of the node. May be the unset marker.

pub fn clear_value(&self)

Sets the current value to the unset marker, notifying the owner.

pub fn short_circuit_null(&self)

Called by a node which has a null-conditional operator applied to it when its source is null: the value of this and all subsequent nodes becomes null and the binding produces null rather than an error.

pub fn set_data_validation_error(&self, error: BindingError)

Notifies the owner of a data validation error.

pub fn set_error(&self, message: &str)

Sets the current value to the unset marker and notifies the owner of the error.

pub fn set_value_or_notification( &self, value_or_notification: Option<BoxedValue>, )

Sets the current value from a value that may be a boxed BindingNotification.

pub fn set_value( &self, value: Option<BoxedValue>, data_validation_error: Option<&BindingError>, )

Sets the current value, notifying the owner.

pub fn validate_non_null_source(&self, source: Option<&BoxedValue>) -> bool

Validates that the source is non-null, raising a node error if it is not.

Trait Implementations

impl Default for NodeState

fn default() -> Self

Returns the “default value” for a type.