Implement IntoIterator for PyDictRef.

[cthulahoops]

Simplify iteration of dictionaries from rust code.

[OddCoincidence]

Rather than implementing this for the specific type, could this be implemented for &PyDict, and then a blanket impl for PyRef<T> (i.e. something like impl<T> IntoIterator for PyRef<T> where &T: IntoIterator).

[cthulahoops]

Good tip. I think we want the other way around: ie. impl<T> IntoIterator for &PyRef<T>, otherwise you always clone.

[cthulahoops]

Or maybe, not... you mean PyDict not PyDictRef.

[cthulahoops]

But, I don't think you implement it for &PyDict because you need the PyRef in order to clone.

[OddCoincidence]

Why do you need to clone? Why not:

struct DictIter<'a> {
    dict: &'a PyDict,
    ...
}

[cthulahoops]

I'll give that a go. Thanks.

[cthulahoops]

I get as far as this

impl<T> IntoIterator for PyRef<T>
where
    T: IntoIterator + PyValue,
{
    type Item = <T as IntoIterator>::Item;
    type IntoIter = <T as IntoIterator>::IntoIter;

    fn into_iter(self) -> Self::IntoIter {
        self.deref().into_iter()
    }
}

which gives:

266 |         self.deref().into_iter()
    |         ^^^^^^^^^^^^ cannot move out of borrowed content

[cthulahoops]

I think I'll merge what I've got here and open a separate PR for this improvement.