# IntoIndex

Sometimes it is more convenient to use another type than `usize` to calculate and store
indices.  This crate provides an `IntoIndex` trait that can be used to convert any type into
an `usize`. For types that implement `TryInto<usize>` this is already implented.  Naturally
some of these conversions are fallible,​ the `into_index()` method may panic in this case. A
`try_into_index()` method that returns a `Result` for handling such errors are available as
well.

# At and AtMut

Further the `At` and `AtMut` traits use `IntoIndex` for providing indexing without the
associated `Output` type that is required for the `Index` and `IndexMut` traits.  A
implementation for std `Vec<T>` is already provided.


# Example

```
use into_index::{IntoIndex, At};
let v = vec![1,2,3];

assert_eq!(*v.at(1u8), 2);
```