trait-cast 0.4.0

//! This example demonstrates how to use the `#[derive(TraitcastableAny)]` proc macro with an enum.
#![cfg_attr(feature = "min_specialization", feature(min_specialization))]
#![cfg_attr(feature = "downcast_unchecked", feature(downcast_unchecked))]
#![feature(ptr_metadata)]

use trait_cast::{TraitcastableAny, TraitcastableAnyInfra};

#[derive(TraitcastableAny)]
#[traitcast_targets(Dog, Cat)]
enum HybridPet {
  Name(String),
}
impl HybridPet {
  fn greet(&self) {
    let Self::Name(name) = self;
    println!("{name}: Hi");
  }
}

impl Dog for HybridPet {
  fn bark(&self) {
    let Self::Name(name) = self;
    println!("{name}: Woof!");
  }
}
impl Cat for HybridPet {
  fn meow(&self) {
    let Self::Name(name) = self;
    println!("{name}: Meow!");
  }
}

trait Dog {
  fn bark(&self);
}
trait Cat {
  fn meow(&self);
}
#[cfg_attr(test, test)]
fn main() {
  // The box is technically not needed but kept for added realism
  let pet = Box::new(HybridPet::Name("Kokusnuss".to_string()));
  pet.greet();

  let castable_pet: Box<dyn TraitcastableAny> = pet;

  let as_dog: &dyn Dog = castable_pet.downcast_ref().unwrap();
  as_dog.bark();

  let as_cat: &dyn Cat = castable_pet.downcast_ref().unwrap();
  as_cat.meow();

  let cast_back: &HybridPet = castable_pet.downcast_ref().unwrap();
  cast_back.greet();
}