Homebrew binding and state to understand how it works

BindingAndState.swift

@propertyDelegate
public struct Binding<Value> {
    public var value: Value {
        get { getValue() }
        nonmutating set { setValue(newValue) }
    }

    public init(getValue: @escaping () -> Value, setValue: @escaping (Value) -> Void) {
        self.getValue = getValue
        self.setValue = setValue
    }

    private let getValue: () -> Value
    private let setValue: (Value) -> Void
	
}

private class Storage<Value> {

    var value: Value

    init(initialValue value: Value) {
        self.value = value
    }

}

@propertyDelegate
public struct State<Value> {

    private let storage: Storage<Value>

    public var value: Value {
        get { storage.value }
	nonmutating set { storage.value = newValue }
    }

    public init(initialValue value: Value) {
    	storage = Storage(initialValue: value)
    }

    public var binding: Binding<Value> {
    	Binding(getValue: { self.value }, setValue: { self.value = $0 })
    }

    public var delegateValue: Binding<Value> { binding }
	
}