OK, with a little bit of tweaking I have come up with a version
that seems to work:
struct List {
payload1: int,
next: Option<~List>,
payload2: f64
}
struct ListMutIterator<'a> {
elem: Option<&'a mut List>
}
impl<'a> Iterator<(&'a mut int, &'a mut f64)> for ListMutIterator<'a> {
fn next(&mut self) -> Option<(&'a mut int, &'a mut f64)> {
let elem = std::util::replace(self, ListMutIterator{elem:None}); //
I think this might be necessary to get around the borrow checker.
let (ret, next) = match elem {
ListMutIterator{elem: Some(&List { payload1: ref mut payload1,
next: ref mut next, payload2: ref mut payload2 })} => {
(Some((payload1, payload2)), match *next {
None => None,
Some(ref mut p) => Some(&mut **p)
})
}
ListMutIterator{elem: None} => (None, None)
};
*self = ListMutIterator{elem:next};
ret
}
}
Perhaps dlist should be updated to use this implementation strategy?
Edward
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