Function any_refection

pub fn any_refection()

动态自省

示例1:

https://doc.rust-lang.org/std/any/index.html

示例2:

use std::any::Any;

trait Foo: Any {
    fn as_any(&self) -> &Any;
}

impl<T: Any> Foo for T {
    fn as_any(&self) -> &Any {
        self
    }
}

struct Bar {}

struct Baz {}

impl PartialEq for Foo {
    fn eq(&self, other: &Foo) -> bool {
        let me = self.as_any();
        let you = other.as_any();
        if me.is::<Bar>() && you.is::<Bar>() {
            true
        } else if me.is::<Baz>() && you.is::<Baz>() {
            true
        } else {
            false
        }
    }
}

fn main() {
    let bar: Bar = Bar {};
    let baz: Baz = Baz {};
    let foo1: &Foo = &bar;
    let foo2: &Foo = &baz;
    println!("{:?}", foo1 == foo2);
}

示例 3:

    use std::any::Any;
    struct UnStatic<'a> { x: &'a i32 }
    fn main() {
        let a = 42;
        let v = UnStatic { x: &a };
        let mut any: &Any;
        //any = &v;  // Compile Error!
    }

修正：

use std::any::Any;
struct UnStatic<'a> { x: &'a i32 }
static ANSWER: i32 = 42;
fn main() {
    let v = UnStatic { x: &ANSWER };
    let mut a: &Any;
    a = &v;
    assert!(a.is::<UnStatic>());
}

示例4:

oso 库应用

https://github.com/osohq/oso/blob/main/languages/rust/oso/src/host/class.rs

示例 5:

bevy_reflect 库应用

https://github.com/bevyengine/bevy/blob/main/crates/bevy_reflect/src/lib.rs