Implement in place sorting of OrderMap and OrderSet about indexmap

[bluss]

I have taken the liberty to edit the original post to better reflect what I think we are seeking. It's your post, so you are free to edit it too, it's a collaboration..

[bluss]

Fixed in #57

[clarfonthey]

You could also use sort_by_key(|elem| elem.0) for the map and just sort for the orderset.

[vitiral]

@clarcharr do you mean it could be named that? I suggested sort for OrderSet in the title of the issue. I'm not sure what sort_by_key means -- you could implement sort_by in addition to sort_keys -- both could be useful!

[clarfonthey]

Sorry; to clarify, you could replace the code in the post with:

pub fn sort_ordermap<K:Ord+Hash, V>(m: &mut OrderMap<K, V>) {
    let mut ordered: Vec<_> = m.drain(..).collect();
    ordered.sort_by_key(|x| x.0);
    m.extend(ordered);
}

pub fn sort_orderset<K:Ord+Hash>(m: &mut OrderSet<K>) {
    let mut ordered: Vec<_> = m.drain(..).collect();
    ordered.sort();
    m.extend(ordered);
}

[vitiral]

Oh, I didn't realize that sort_by_key was a thing! Thanks!

[bluss]

I agree with this feature request. No comment on whether it is possible easily

[bluss]

A side note about sort_by_key, is that the key version sometimes will need to clone the keys when the _by version does not.

[vitiral]

sort_by would be a good first start. Additional methods (like sort_keys) can be added later at other's requests.

[bluss]

Implemented as an experiment in #57, (building upon the retain in place PR, so that one needs to merge first).

Yes, instead of Vec's .sort() ordermap should probably have .sort_keys(), that sounds nice