Trait UpdateValue

pub trait UpdateValue: DefinedAt {
    type Value;

    // Required method
    fn try_update_value<U>(
        &self,
        fun: impl FnOnce(&mut Self::Value) -> U,
    ) -> Option<U>;

    // Provided method
    fn update_value(&self, fun: impl FnOnce(&mut Self::Value)) { ... }
}

A variation of the Update trait that provides a signposted “always-non-reactive” API. E.g. for StoredValue.

Required Associated Types

type Value

The type of the value contained in the value.

Required Methods

fn try_update_value<U>( &self, fun: impl FnOnce(&mut Self::Value) -> U, ) -> Option<U>

Updates the value, returning the value that is returned by the update function, or None if the value has already been disposed.

Provided Methods

fn update_value(&self, fun: impl FnOnce(&mut Self::Value))

Updates the value.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<T> UpdateValue for T

where T: WriteValue,

type Value = <T as WriteValue>::Value