nonempty-collections

Happy Remembrance Day.

Added

• NonEmptyIterator::intersperse, finally! Iterator::intersperse within std
  is still not stabilized after years of waiting, and its annoying to depend on
  itertools just for this.
• More impls of FromNonEmptyIterator. You can now fold non-empty iterators
  into String, BTreeMap, BTreeSet, PathBuf, and ().

Added

• The Singleton trait.
• NonEmptyIterator::unzip.
• Extend impls for NESet, NEMap, and NEIndexMap.

Added

• Various AsRef impls.

Fixed

• Overly restrictive bounds on the PartialEq impl for NEMap.

Five months since the big changes and no major issues. If there are, we can now
fix them in the normal Semver way.

Added

• nev![a; n] syntax (similar to vec![a; n])

Changed

• Bumped the Rust Edition to 2024.

Added

• iter_mut() to NEVec, NEMap, and NEIndexMap
• peekable() to NonEmptyIterator
• remove(), swap_remove(), retain(), and retain_mut() to NEVec.
• AsRef<[T]> for NESlice.

Huge thanks to Rinde van Lon for implementing the bulk of these new changes and additions. Thanks to him, the various non-empty collections now have much better performance characteristics.

Changed

• BREAKING: Redesign of NonEmptyIterator:
  • NonEmptyIterator is now bounded by IntoIterator and has default
    implementations of all methods (i.e. it is a marker trait).
  • NonEmptyIterator::first() is renamed to next() and the old implementation of next() is removed.
  • NonEmptyIterator::all() now consumes self
  • NonEmptyIterator::any() now consumes self
  • NonEmptyIterator::nth() now consumes self
  • NonEmptyIterator::take(usize) -> NonEmptyIterator::take(NonZeroUsize) and doesn't panic anymore
• BREAKING: NEVec::truncate(usize) -> NEVec::truncate(NonZeroUsize) and doesn't panic anymore
• BREAKING: Capacities for all collections now use NonZeroUsize instead of usize:
  • with_capacity(NonZeroUsize)
  • with_capacity_and_hasher(NonZeroUsize)
  • capacity() -> NonZeroUsize
• BREAKING: All fields are now private for NEVec, NEMap, NESet, and NESlice
• BREAKING: Removed:
  • NESlice::new(&T, &[T])
  • IntoIteratorProxy
• BREAKING: Methods that are no longer const:
  • NEVec::new()
  • NEVec::first()
• BREAKING: non-empty maps and sets now behave similarly to their possibly
  empty counter parts: when created from an iterator with duplicates, the last
  occurence is kept.
• BREAKING: Consistent API, new naming to align with Rust's naming
  conventions and indicate the fallibility of the function:
  • from_vec to try_from_vec
  • from_map to try_from_map
  • from_slice to try_from_slice
  • from_set to try_from_set.
• BREAKING: IteratorExt is removed in favor of IntoIteratorExt. Now it's
  possible to call try_into_nonempty_iter() instead of to_nonempty_iter() on
  all regular iterators because regular iterators also implement IntoIterator.
• BREAKING: .iter(), .iter_mut(), etc, are now prefixed with nonempty_
• FromNonEmptyIterator<T> is now implemented for HashSet<T, S> instead of
  HashSet<T> (with the default hasher).

Fixed

• Fixes bug in PartialEq for NEIndexMap, previously, maps with unequal lengths
  would be considered equal if the shorter map would contain the same values as
  the longer map.
• Fixes bug in NEMap::with_capacity() and NESet::with_capacity(), it wasn't
  possible to call this method without explicitly specifying the type for S
  (the hasher). For this method it is assumed that it always uses the default
  hasher (just like in std), in case the user wants to specify the hasher
  with_capacity_and_hasher() can be used. The fix moved the method into the
  proper impl block.

Added

• New feature either: adds NEEither an extension to either::Either.
• New feature itertools: adds a new NonEmptyItertools trait that is an
  extension of the NonEmptyIterator similar to how Itertools extends
  Iterator. So far, cartesian_product(), sorted_by_key(), and
  all_unique() are implemented.
• NonEmptyIterator::find() the equivalent of Iterator::find().
• IntoNonEmptyIterator for &NEVec, &NEIndexMap, &NEMap, &NESet,
  &NESlice, &[T; $i] where $i > 0 (these previously only existed for their
  owned equivalents)
• NESlice::from_slice() is now const
• Index<usize> for NESlice
• All public types now implement Debug
• Aliases ne_vec for nev, ne_hashset for nes, and ne_hashmap for nem.
• Strict lint configuration
• The rust version to which the library is build is now pinned, to avoid accidental breakage.
• A justfile that allows to run
  pre-configured commands to check the codebase. E.g. just lint or just test.
• Benchmarks for Vec versus NEVec.
• Added .iter() methods to all collections returning a regular Iterator.

Added

• NonEmptyIterator::group_by.
• NVec::sort_by and NEVec::sort_by_key.
• An impl of Extend for NEVec.

Fixed

• NEVec::sort avoids a second internal sort.

Added

• Missing FromNonEmptyIterator for HashMap.

Added

• serde support for NEMap and NESet.

Fixed

• Ownership issues in nem! when using non-Copy types.

Added

• Implementation of NonEmptyIterator for fixed-sized stdlib Arrays.

Added

• Added NEVec::partition_point to match the function of the same name in std.

Fixed

• Render feature-gated types on docs.rs.

Fixed

• More edge cases involving NEChunks.

Fixed

• IntoIterator for NEChunks yielding the wrong type.
• NonEmptyIterator for NEChunks missing a cutoff condition.

Added

• The missing IntoIterator impl for NEChunks.
• IntoIteratorExt for direct conversion from anything that implements IntoIterator. Thanks to Rinde van Lon.

Fixed

• A bug involving repeated keys in NEMap and NEIndexedMap. Thanks to Rinde van Lon.

Added

• NEIndexMap, thanks to Rinde van Lon.
• NonEmptyIterator::max_by_key and NonEmptyIterator::min_by_key, also thanks to Rinde.
• NEVec::with_capacity
• NEVec::nonempty_chunks and NESlice::nonempty_chunks

Changed

• BREAKING: All len implementations and NonEmptyIterator::count have had their return type changed to NonZeroUsize.

Added

• NonEmptyIterator::reduce, which yields a concrete Self::Item instead of an Option.
• IteratorExt::to_nonempty_iter for converting any given Iterator into a non-empty one (if possible).
• The NEVec::dedup* series for removing duplicate items in-place.

Fixed

• Account for potentially duplicated head value when converting into an NESet from other nonempty iterators.

Added

• FromNonEmptyIterator impls for NEMap and NESet.
• Debug, Clone, PartialEq, and Eq for NEMap.

Added

• NESlice for when what you have on hand is already borrowed. Thanks again to Greg Shuflin.

Added

• A FromNonEmptyIterator instance for Result, meaning you can collect into a guaranteed Result<NEVec<...>, Error> (or other nonempty type). Thanks to Greg Shuflin.

Added

• Missing IntoNonEmptyIterator instances.
• Missing Intoiterator instance for FlatMap.

Fixed

• Incorrect IntoIterator for Take.