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use crate::grind::Grinder;
use std;
pub struct Peekable<T: Grinder> {
inner: T,
peek: T::Item,
}
impl<T> Peekable<T>
where
T: Grinder,
{
pub fn new(mut inner: T) -> Peekable<T> {
let peek = inner.next();
Peekable {
inner: inner,
peek: peek,
}
}
pub fn peek(&self) -> &T::Item {
&self.peek
}
}
impl<T> Grinder for Peekable<T>
where
T: Grinder,
{
type Item = T::Item;
type Error = T::Error;
fn emit(&mut self, err: Self::Error) {
self.inner.emit(err)
}
fn next(&mut self) -> Self::Item {
let mut n = self.inner.next();
std::mem::swap(&mut self.peek, &mut n);
n
}
}
impl<T> From<T> for Peekable<T>
where
T: Grinder,
{
fn from(inner: T) -> Peekable<T> {
Peekable::new(inner)
}
}
