has-some

Implement the opposite of is_empty in order to allow better semantics for iterator filters and other situations where !T.is_empty() is counterintuitive.

While using is_empty in an iterator filter method is relative verbose anyway, when that iterator has a reference as an item type, it still stands that the semantics of "not is_empty" are annoying (well, to me) when "has some" is clearer.

That's all this does - it provides the opposite of is_empty when what you really want to know is "does it contain stuff".

Examples

It's not really rocket science, but here you go with an example where is_empty passed as a function reference to an iterator filter does work:

use has_some::HasSome

let vector = vec!["some_data".to_owned(), "".to_owned(), "more data".to_owned(), "".to_owned()];
let vector2 = vector.clone();

// If you want the empties, you can do
let empties = vector.into_iter().filter(String::is_empty).collect::<Vec<String>>();
assert_eq!(["", ""], empties.as_slice());

// If you want the non-empties, you can now do
let non_empties = vector2.into_iter().filter(String::has_some).collect::<Vec<String>>();
assert_eq!(["some_data", "more data"], non_empties.as_slice());