Trait Selector 

pub trait Selector {
    type Output;

    // Required methods
    fn select(&mut self, candidate: Candidate<'_>) -> Option<Self::Output>;
    fn description(&self) -> String;

    // Provided methods
    fn find(self) -> Finder<One<Self>>
       where Self: Sized { ... }
    fn find_all(self) -> Finder<All<Self>>
       where Self: Sized { ... }
}

A type that traverses the widget tree to “select” data and produce some output.

Required Associated Types

type Output

The output type of the Selector.

For most selectors, this will normally be a [Target]. However, some selectors may want to return a more limited type to encode the selection guarantees in the type system.

For instance, the implementations of String and str of Selector return a [target::Text] instead of a generic [Target], since they are guaranteed to only select text.

Required Methods

fn select(&mut self, candidate: Candidate<'_>) -> Option<Self::Output>

Performs a selection of the given [Candidate], if applicable.

This method traverses the widget tree in depth-first order.

fn description(&self) -> String

Returns a short description of the Selector for debugging purposes.

Provided Methods

fn find(self) -> Finder<One<Self>>

where Self: Sized,

Returns a [widget::Operation] that runs the Selector and stops after the first Output is produced.

fn find_all(self) -> Finder<All<Self>>

where Self: Sized,

Returns a [widget::Operation] that runs the Selector for the entire widget tree and aggregates all of its Output.

Implementations on Foreign Types

impl Selector for &str

type Output = Text

fn select( &mut self, candidate: Candidate<'_>, ) -> Option<<&str as Selector>::Output>

fn description(&self) -> String

impl Selector for String

type Output = Text

fn select( &mut self, candidate: Candidate<'_>, ) -> Option<<String as Selector>::Output>

fn description(&self) -> String

impl Selector for Id

type Output = Target

fn select( &mut self, candidate: Candidate<'_>, ) -> Option<<Id as Selector>::Output>

fn description(&self) -> String

impl Selector for Point

type Output = Target

fn select( &mut self, candidate: Candidate<'_>, ) -> Option<<Point as Selector>::Output>

fn description(&self) -> String

Implementors

impl<F, T> Selector for F

where F: FnMut(Candidate<'_>) -> Option<T>,

type Output = T