Derive Macro AsAny

#[derive(AsAny)]

Trait amplify::AsAny allows simple conversion of any type into a generic “thick” pointer &dyn Any (see [::core::any::Any]), that can be later converted back to the original type with a graceful failing for all other conversions. AsAny derive macro allows to implement this trait for arbitrary time without much hussle:

Example

extern crate amplify;
use amplify::AsAny;

#[derive(AsAny, Copy, Clone, PartialEq, Eq, Debug)]
struct Point {
    pub x: u64,
    pub y: u64,
}

#[derive(AsAny, PartialEq, Debug)]
struct Circle {
    pub radius: f64,
    pub center: Point,
}

let mut point = Point { x: 1, y: 2 };
let point_ptr = point.as_any();

let mut circle = Circle {
    radius: 18.,
    center: point,
};
let circle_ptr = circle.as_any();

assert_eq!(point_ptr.downcast_ref(), Some(&point));
assert_eq!(circle_ptr.downcast_ref(), Some(&circle));
assert_eq!(circle_ptr.downcast_ref::<Point>(), None);

let p = point_ptr.downcast_ref::<Point>().unwrap();
assert_eq!(p.x, 1)