Trait BackingField 

pub trait BackingField<T> {
    // Required methods
    fn equals(&self, value: &T, comparer: &dyn Fn(&T, &T) -> bool) -> bool;
    fn store(&self, value: T);
}

A backing field that AbstractNotifyPropertyChanged::set_and_raise reads and assigns: a Cell for a value that is Copy, a RefCell for the others (ref T backingField). It is ferroui-system’s, which the reactive objects of ferroui-reactiveui share. A backing field that a setter reads and assigns through a shared reference: a Cell for a value that is Copy, a RefCell for the others (ref T backingField).

The setters of the reactive libraries take &impl BackingField<T>, so that one setter serves both kinds of field.

use ferroui_system::component_model::BackingField;
use std::cell::{Cell, RefCell};

fn set<T: PartialEq>(field: &impl BackingField<T>, value: T) -> bool {
    if field.equals(&value, &|a, b| a == b) {
        return false;
    }
    field.store(value);
    true
}

let age = Cell::new(3);
assert!(set(&age, 4));
assert!(!set(&age, 4));
let name = RefCell::new(String::from("a"));
assert!(set(&name, String::from("b")));
assert_eq!(*name.borrow(), "b");

Required Methods

fn equals(&self, value: &T, comparer: &dyn Fn(&T, &T) -> bool) -> bool

Whether the value of the field equals value by comparer.

fn store(&self, value: T)

Assigns value to the field.

Dyn Compatibility

This trait is dyn compatible.

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

Implementations on Foreign Types

impl<T> BackingField<T> for Cell<T>

where T: Copy,

fn equals(&self, value: &T, comparer: &dyn Fn(&T, &T) -> bool) -> bool

fn store(&self, value: T)

impl<T> BackingField<T> for RefCell<T>

fn equals(&self, value: &T, comparer: &dyn Fn(&T, &T) -> bool) -> bool

fn store(&self, value: T)

Implementors