[][src]Crate non_empty_collections

Non-empty hash map and hash set implementations based on indexmap::IndexMap and indexmap::IndexSet respectively, which are guaranteed to be non-empty by the type system of Rust.

pipeline status crates.io docs.rs

[Release docs]

[Master docs]

Currently not all the methods of IndexMap or IndexSet are ported to NonEmptyIndexMap and NonEmptyIndexSet, so if you are missing something, PRs are welcome! :)

Right now both implementations are too naïve: non-emptiness is achieved by declaring map and set types as a pair of an element and the rest of the collection. While the idea itself is not bad, it adds an additional overhead on basically every operation since we have to execute everything twice: on the first element and then on the rest.

Both collections are coming with serde de- and serializers, but if you don't need them and want to save some space and/or compilation time you can always disable it by disabling a feature serde_support (which is on by default).


pub use index_map::NonEmptyIndexMap;
pub use index_set::NonEmptyIndexSet;



Non-empty hash map implementation.


Non-empty hash set implementation.



An error that might happen during transactions.