deref_for_oo.rs

// Source: https://gist.github.com/dns2utf8/6550ff8ff35205bc718ea8ca4f8b6217

use core::ops::{Deref, DerefMut};
use std::any::Any;

#[derive(Default, Clone, Debug)]
pub struct Part {
    pub count: u16,
}

#[derive(Default, Clone, Debug)]
pub struct Apartments {
    pub content: Part,
    pub number: u16,
}
impl Deref for Apartments {
    type Target = Part;

    fn deref(&self) -> &Self::Target {
        &self.content
    }
}
impl DerefMut for Apartments {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.content
    }
}

#[derive(Default, Clone, Debug)]
pub struct Roads {
    pub content: Part,
    pub length: u16,
}
impl Deref for Roads {
    type Target = Part;

    fn deref(&self) -> &Self::Target {
        &self.content
    }
}

trait ComponentPart {
    fn part(&self) -> &Part;
    fn as_any(&self) -> &dyn Any;
}
impl ComponentPart for Apartments {
    fn part(&self) -> &Part {
        &self.content
    }
    fn as_any(&self) -> &dyn Any {
        self
    }
}
impl ComponentPart for Roads {
    fn part(&self) -> &Part {
        &self.content
    }
    fn as_any(&self) -> &dyn Any {
        self
    }
}

fn main() {
    let mut a: Apartments = Default::default();
    let r: Roads = Default::default();

    a.count += 5;

    assert_eq!(2 + 3, a.count + r.count);

    // Liste mit VTable
    let l: Vec<Box<dyn ComponentPart>> = vec![Box::new(a), Box::new(r)];
    for (i, p) in l.iter().enumerate() {
        let debug_string = get_debug_string(p.as_any());
        println!("{}: {:?} => {}", i, p.part(), debug_string);
    }
}

fn get_debug_string(value: &dyn Any) -> String {
    match (value.downcast_ref::<Apartments>(), value.downcast_ref::<Roads>()) {
        (Some(a), _) => format!("{:?}", a),
        (_, Some(r)) => format!("{:?}", r),
        e => format!("Unknown Type: {:?}", e),
    }
}

Run on play.rust-lang.org