Add accessor by reference to immutable

[carlomilanesi]

Currently, if I have:

#[nutype(validate(not_empty), derive(Debug, PartialEq, Clone))]
pub struct Username(String);

let u = Username::try_new("Jack").unwrap();
assert_eq!(u.into_inner(), "Jack");
assert_eq!(u.into_inner(), "Jack");

At the last line I get the error:

use of moved value: `u`

Instead, with my change, I can write:

let u = Username::try_new("Jack").unwrap();
assert_eq!(u.inner(), "Jack");
assert_eq!(u.inner(), "Jack");

[greyblake]

@carlomilanesi Hi!
Thanks for your effort, though I have to decline your contribution.
For your case you should derive AsRef and use it:

use nutype::nutype;

#[nutype(
    validate(not_empty),
    derive(Debug, PartialEq, Clone, AsRef)
)]
pub struct Username(String);

fn main() {
    let u = Username::try_new("Jack").unwrap();
    assert_eq!(u.as_ref(), "Jack");
    assert_eq!(u.as_ref(), "Jack");
}

I hope that helps!

[carlomilanesi]

Ok, but I think you should explain better in documentation the uses of into_inner and of as_ref to access the value.

[greyblake]

@carlomilanesi Thanks for you feedback!
I've updated the docs #200