Type erased vector. All elements have the same type.
Designed to be type-erased as far as possible - most of the operations does not know about concrete type.
Only destruct operations have additional overhead of indirect call.
let mut vec: AnyVec = AnyVec::new::<String>();
{
// Typed operations.
let mut vec = vec.downcast_mut::<String>().unwrap();
vec.push(String::from("0"));
vec.push(String::from("1"));
vec.push(String::from("2"));
}
let mut other_vec: AnyVec = AnyVec::new::<String>();
// Fully type erased element move from one vec to another
// without intermediate mem-copies.
//
// Equivalent to:
//
// let element = vec.swap_remove(0);
// other.push(element);
unsafe{
let element: &mut[u8] = other_vec.push_uninit(); // allocate element
vec.swap_remove_into(0, element); // swap_remove
}
// Output 2 1
for s in vec.downcast_ref::<String>().unwrap().as_slice(){
println!("{}", s);
}
- type_erased_vec. Allow to store
Vec<T>in type erased way, but you need to perform operations, you need to "cast" to concrete type first. - untyped_vec. Some operations like
len,capacityperformed without type knowledge; but the rest - require concrete type.