Struct gtk4::ExpressionWatch

#[repr(transparent)]
pub struct ExpressionWatch { /* private fields */ }

An opaque structure representing a watched Expression.

The contents of ExpressionWatch should only be accessed through the provided API.

Implementations

impl ExpressionWatch

pub fn evaluate(&self) -> Option<Value>

Evaluates the watched expression and on success stores the result in value.

This is equivalent to calling Expression::evaluate() with the expression and this pointer originally used to create watch.

value

an empty GValue to be set

Returns

TRUE if the expression could be evaluated and value was set

pub fn evaluate_as<V: for<'b> FromValue<'b> + 'static>(&self) -> Option<V>

Similar to Self::evaluate but panics if the value is of a different type.

pub fn unwatch(&self)

Stops watching an expression.

See Expression::watch() for how the watch was established.

Trait Implementations

impl Clone for ExpressionWatch

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ExpressionWatch

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

Formats the value using the given formatter.

impl Hash for ExpressionWatch

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

Feeds this value into the given Hasher.

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

Feeds a slice of this type into the given Hasher.

impl Ord for ExpressionWatch

fn cmp(&self, other: &ExpressionWatch) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl PartialEq<ExpressionWatch> for ExpressionWatch

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

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

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd<ExpressionWatch> for ExpressionWatch

fn partial_cmp(&self, other: &ExpressionWatch) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for ExpressionWatch

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for ExpressionWatch

impl StructuralEq for ExpressionWatch

impl StructuralPartialEq for ExpressionWatch