Cannot return HashMap value.

[irishgreencitrus]

I have two structs. One holds a HashMap of a String to the other. When I try to implement a method getting the value of the hashmap from a string, it only returns a borrow, and I cannot implement the Clone trait due to the type containing a RegistryKey. Any help is appreciated.

struct PackageManager {
    install_callback: RegistryKey,
    packages: Vec<String>,
}
struct PackageScope {
    builtins: HashMap<String, PackageManager>,
    user: String,
}
impl UserData for PackageManager { ... }
impl UserData for PackageScope {
     fn add_methods<'lua, M: LuaUserDataMethods<'lua, Self>>(methods: &mut M) {
          methods.add_meta_method(LuaMetaMethod::Index, |lua, this: &Self, key: String| {
               let ret = this.builtins.get(&key);
               return match ret {
                   Some(val) => Ok(val),
                   None      => Err(LuaError::RuntimeError("Invalid key".to_string()))
               };
           });
       }
}

[khvzak]

There are few options:

1. Store PackageManager inside Rc<RefCell>:

struct PackageScope {
    builtins: HashMap<String, Rc<RefCell<PackageManager>>>,
    user: String,
}

Then you can send it to Lua (cloned by reference).

2. Store RegistryKey as Rc<RegistryKey>, this would allow to implement Clone for PackageManager

3. Store PackageManager directly inside Lua and refer to each instance via RegistryKey, eg:

struct PackageScope {
    builtins: HashMap<String, RegistryKey>,
    user: String,
}

[irishgreencitrus]

There are few options:

1. Store PackageManager inside Rc<RefCell>:

struct PackageScope {

    builtins: HashMap<String, Rc<RefCell<PackageManager>>>,

    user: String,

}

Then you can send it to Lua (cloned by reference).

2. Store RegistryKey as Rc<RegistryKey>, this would allow to implement Clone for PackageManager

3. Store PackageManager directly inside Lua and refer to each instance via RegistryKey, eg:

struct PackageScope {

    builtins: HashMap<String, RegistryKey>,

    user: String,

}

Thanks so much for the help!