Implement specialized nth_back() for Box and Windows.
Hi there, this is my first pull request to rust :-)
I started implementing some specializations for DoubleEndedIterator::nth_back() and these are the first two. The problem has been discussed in #54054 and nth_back() is tracked in #56995.
I'm stuck with the next implementation so I though I do a PR for the ones I'm confident with to get some feedback.
Add some more notes to the documentation:
- Mention that the median can be found if we used `len() / 2`.
- Mention that this function is usually called "kth element" in other libraries.
Address some comments in PR:
- Change wording on some of the documentation
- Change recursive function into a loop
Update name to `partition_at_index` and add convenience return values.
Address reviewer comments:
- Don't swap on each iteration when searching for min/max element.
- Add some docs about when we panic.
- Test that the sum of the lengths of the output matches the length of the input.
- Style fix for for-loop.
Address more reviewer comments
Fix Rng stuff for test
Fix doc test build
Don't run the partition_at_index test on wasm targets
Miri does not support entropy for test partition_at_index
In bluss/indexmap#88, we found that there was no easy way to implement
`Debug` for our `IterMut` and `Drain` iterators. Those are built on
`slice::IterMut` and `vec::Drain`, which implement `Debug` themselves,
but have no other way to access their data. With a new `as_slice()`
method, we can read the data and customize its presentation.
There are two big categories of changes in here
- Removing lifetimes from common traits that can essentially never user a lifetime from an input (particularly `Drop` & `Debug`)
- Forwarding impls that are only possible because the lifetime doesn't matter (like `impl<R: Read + ?Sized> Read for &mut R`)
I omitted things that seemed like they could be more controversial, like the handful of iterators that have a `Item: 'static` despite the iterator having a lifetime or the `PartialEq` implementations where the flipped one cannot elide the lifetime.
Additionally, the root implementation was changed a bit: it now uses
`all` instead of coding that logic manually.
To avoid duplicate code, the inherent `[T]::is_sorted_by` method now
calls `self.iter().is_sorted_by(...)`. This should always be inlined
and not result in overhead.
Doc total order requirement of sort(_unstable)_by
I took the definition of what a total order is from the Ord trait
docs. I specifically put "elements of the slice" because if you
have a slice of f64s, but know none are NaN, then sorting by
partial ord is total in this case. I'm not sure if I should give
such an example in the docs or not.
r? @GuillaumeGomez
Add slice::rchunks(), rchunks_mut(), rchunks_exact() and rchunks_exact_mut()
These work exactly like the normal chunks iterators but start creating
chunks from the end of the slice.
----
The new iterators were motivated by a [comment](https://github.com/rust-lang/rust/issues/47115#issuecomment-424141121) by @DutchGhost.
~~~This currently includes the commits from https://github.com/rust-lang/rust/pull/54537 to not have to rename things twice or have merge conflicts. I'll force-push a new version of the branch ones those are in master.~~~
Also the stabilization tracking issue is just some number right now. I'll create the corresponding issue once this is reviewed and otherwise mergeable.
cc @DutchGhost
I took the definition of what a total order is from the Ord trait
docs. I specifically put "elements of the slice" because if you
have a slice of f64s, but know none are NaN, then sorting by
partial ord is total in this case. I'm not sure if I should give
such an example in the docs or not.
