Alternatives to returning a Bundle to feed to commands.spawn?

[tender flume]

I've read
https://github.com/bevyengine/bevy/issues/3227

and I see bundles can't be returned as objects.

I'm trying to make a sample cube for commands.spawn to spawn like so:
`
/// cube with physics
pub fn CUBE(
length: usize //length, width, height of cube
) -> dyn Bundle {
///code, code
return cube_bundle
}

/// some other function ....
{
commands.spawn(CUBE(5.0));
}
`
How would I achieve something similar to the above since bundles can't be returned as objects?

[halcyon zinc]

Generally the simplest pattern is to just take &mut Commands

Or create a custom Command you can pass to Commands::add

[tender flume]

example?

[halcyon zinc]

So you could do:

pub fn spawn_cube(
  length: usize, //length, width, height of cube
  commands: &mut Commands
) -> Entity {
  ///code, code
  commands
    .spawn(CubeBundle { length, /*...*/})
    .id()
}

fn my_system(mut commands: Commands) {
  let cube = spawn_cube(
    123,
    //length, width, height of cube
    &mut commands
  );
}

Or a custom Command:

struct SpawnCube {
  length: usize,
  //length, width, height of cube
}

impl Command for SpawnCube {
  fn write(self, world: &mut World) {
    world.spawn(CubeBundle { length, /*...*/});
  }
}

fn my_system(mut commands: Commands) {
  commands.add(SpawnCube {
    length: 123,
    //length, width, height of cube
  });
}

(there's also EntityCommand for per-entity commands)