use super::{Element, Elements};
impl<'e, 't> IntoIterator for &'e Elements<'t> {
type Item = &'e Element<'t>;
type IntoIter = BorrowedElementsIterator<'e, 't>;
fn into_iter(self) -> Self::IntoIter {
match self {
Elements::None => BorrowedElementsIterator::None,
Elements::Single(element) => BorrowedElementsIterator::Single(Some(element)),
Elements::Multiple(elements) => {
BorrowedElementsIterator::Multiple(elements, 0)
}
}
}
}
#[derive(Debug)]
pub enum BorrowedElementsIterator<'e, 't> {
None,
Single(Option<&'e Element<'t>>),
Multiple(&'e [Element<'t>], usize),
}
impl<'e, 't> Iterator for BorrowedElementsIterator<'e, 't> {
type Item = &'e Element<'t>;
#[inline]
fn next(&mut self) -> Option<&'e Element<'t>> {
match self {
BorrowedElementsIterator::None => None,
BorrowedElementsIterator::Single(element) => element.take(),
BorrowedElementsIterator::Multiple(elements, index) => {
let next = elements.get(*index);
*index += 1;
next
}
}
}
}
#[test]
fn iter() {
macro_rules! test {
($elements:expr, $expected:expr $(,)?) => {{
let elements = &$elements;
let actual: Vec<&Element> = elements.into_iter().collect();
let expected: Vec<&Element> = $expected;
assert_eq!(
actual, expected,
"Actual element iteration doesn't match expected",
);
}};
}
test!(Elements::None, vec![]);
test!(Elements::Single(text!("a")), vec![&text!("a")]);
test!(
Elements::Multiple(vec![]), vec![],
);
test!(
Elements::Multiple(vec![text!("a")]), vec![&text!("a")],
);
test!(
Elements::Multiple(vec![text!("a"), text!("b")]),
vec![&text!("a"), &text!("b")],
);
test!(
Elements::Multiple(vec![text!("a"), text!("b"), text!("c")]),
vec![&text!("a"), &text!("b"), &text!("c")],
);
}