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use std::iter::{Enumerate, Peekable};
pub struct TemplateLoop<I>
where
I: Iterator,
{
iter: Peekable<Enumerate<I>>,
}
impl<I> TemplateLoop<I>
where
I: Iterator,
{
#[inline]
pub fn new(iter: I) -> Self {
TemplateLoop {
iter: iter.enumerate().peekable(),
}
}
}
impl<I> Iterator for TemplateLoop<I>
where
I: Iterator,
{
type Item = (<I as Iterator>::Item, LoopItem);
#[inline]
fn next(&mut self) -> Option<(<I as Iterator>::Item, LoopItem)> {
self.iter.next().map(|(index, item)| {
(
item,
LoopItem {
index,
first: index == 0,
last: self.iter.peek().is_none(),
},
)
})
}
}
#[derive(Copy, Clone)]
pub struct LoopItem {
pub index: usize,
pub first: bool,
pub last: bool,
}