query_interface

Dynamically query a type-erased object for any trait implementation

Documentation

Example: ```rust

[macro_use]

extern crate query_interface;

use query_interface::{Object, ObjectClone}; use std::fmt::Debug;

[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]

struct Foo;

interfaces!(Foo: ObjectClone, Debug, Bar);

trait Bar { fn dosomething(&self); } impl Bar for Foo { fn dosomething(&self) { println!("I'm a Foo!"); } }

fn main() { let obj = Box::new(Foo) as Box; let obj2 = obj.clone(); println!("{:?}", obj2);

obj2.query_ref::<Bar>().unwrap().do_something();  // Prints: "I'm a Foo!"

} ```

In short, this allows you to pass around Objects and still have access to any of the (object-safe) traits implemented for the underlying type. The library also provides some useful object-safe equivalents to standard traits, including ObjectClone, ObjectPartialEq, ObjectPartialOrd, ObjectHash.

To improve usability, the non-object-safe versions of the traits are implemented directly on the Object trait object, allowing you to easily clone Objects and store them in collections.