Shared via Rust Playground

playground.rs

#![feature(core_intrinsics)]

pub trait Deserialize: Sized {
    fn deserialize(String) -> Self;
}

struct Position(i32, i32);
struct Velocity(i32, i32);

impl Deserialize for Position {
    fn deserialize(s: String) -> Self {
        Position(5, 5)
    }
}

pub struct EntityBuilder;

impl EntityBuilder {
    pub fn with<T>(self, v: T) {
        println!("test");
    }
}

use std::collections::HashMap;
use std::intrinsics;

pub struct Deserializer {
    pub map: HashMap<String, Box<Fn(EntityBuilder, String)>>,
}

fn main() {
    let x = |e: EntityBuilder, s: String| {
        e.with(Position::deserialize(s));
    };
    
    let mut deserializer = Deserializer { map: HashMap::new() };
    deserializer.map.insert("Test".to_string(), Box::new(x));
    
    let entity_builder = EntityBuilder;
    
    let create = deserializer.map.get("Test").unwrap();
    create(entity_builder, "Test".to_string());
}