Excerpts from Huon Wilson's message of 2013-12-06 00:26:36 -0800:
> One could have an Iterator<(&mut int, &mut int)>, where the references
> point to just the fields. Off the top of my head:
Sure. (This is not so good when there are a lot of fields.)
> 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, None); // I think this
> might be necessary to get around the borrow checker.
>
> let (ret, next) = match elem {
> Some(&List { payload1: ref mut payload1, next: ref mut
> next, payload2: ref mut payload2 }) => {
> (Some((payload1, payload2)), next.as_mut_ref())
I fixed some of the egregious type-checking errors, but this one has me
stuck. There is no as_mut_ref() in the version of Rust I'm running, and
the plausible replacement mut_ref() doesn't do what I want:
Huon.rs|24 col 37 error| mismatched types: expected
`std::option::Option<&mut List>` but found `std::option::Option<&mut ~List>`
(expected struct List but found ~-ptr)
(Because, of course, the thing inside the option is a ~List, not a
List).
Cheers,
Edward
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