Trait WithOptional 

pub trait WithOptional: DefinedAt {
    type Value: ?Sized;

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

    // Provided method
    fn with<U>(&self, fun: impl FnOnce(Option<&Self::Value>) -> U) -> U { ... }
}

An alternative With trait that works with Option<Withable> types.

Required Associated Types

type Value: ?Sized

The type of the value contained in the signal.

Required Methods

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

Subscribes to the signal, applies the closure to the value, and returns the result, or None if the signal has already been disposed.

Provided Methods

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

Subscribes to the signal, applies the closure to the value, and returns the result.

Panics

Panics if you try to access a signal that has been disposed.

Dyn Compatibility

This trait is not dyn compatible.

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

Implementations on Foreign Types

impl<T> WithOptional for Option<T>

where Option<T>: DefinedAt, T: With, <T as With>::Value: Sized,

type Value = <T as With>::Value

fn try_with<U>( &self, fun: impl FnOnce(Option<&<Option<T> as WithOptional>::Value>) -> U, ) -> Option<U>

Implementors