Macro bbecs::get_resource_mut

macro_rules! get_resource_mut {
    ($resource:ident, $world:expr, $name:expr) => { ... };
}

Get a mutable reference to a resource from the provided world so that we can change it. This will probably need to be put into a block or dropped so that other queries can work.

use bbecs::world::World;
use bbecs::{get_resource, get_resource_mut};
use crate::bbecs::world::WorldMethods;
use crate::bbecs::resources::resource::ResourceCast;

let mut world = World::new();
world.add_resource("size".to_string(), 15.0_f32);

{
    let size: &mut f32;
    get_resource_mut!(size, world, "size");

    *size += 1.0;
}

let size: &f32;
get_resource!(size, world, "size");
assert_eq!(*size, 16.0_f32);