Implement Into<usize> for NodeId

[wlinna]

Implements Into<usize> for NodeId. This implementation returns index0() since 0-based indexing is more conventional.

A more explicit alternative would be making index0 public. This would have the benefit of not being "less astonishing", since one might not expect Into returning a different value.

For background info, see the related issue

[wlinna]

I just realized that impl fmt::Display for NodeId gives index1-based representation, so these two indeed give confusing results now. I'm not sure if I should change this though. Opinions?

[saschagrunert]

Yes I think we should return the same, so the index1 based result. :)

[wlinna]

Should I then implement this for both NonZeroUsize and usize?

[saschagrunert]

I think it does not hurt, yeah.

[saschagrunert]

LGTM, thanks

[wlinna]

Sorry, I was too hasty, wasn't focusing well enough apparently. I just noticed on my own project, that with these two impls, I have a hard time using into.

Now I get this error

error[E0283]: type annotations needed for `indextree::id::NodeId`
   --> src/octree.rs:144:86
144 |             let children: Vec<usize> = node_i.children(&self.arena).into_iter().map(|c: NodeId| -> usize { c.into()}).collect();
    |                                                                                      ^ consider giving this closure parameter a type
    = note: cannot resolve `indextree::id::NodeId: std::convert::Into<_>`

I tried specifying types in different places, or explicitly calling Into::<usize>::into(c), and things like that, but I still get the same error.

[wlinna]

Nevermind. On further inspection, I noticed that the problem is unrelated.

Glad to contribute. Thanks for the rapid communication!

[saschagrunert]

Sounds good, I’m glad that it helps on your side. 👍