Crate refset 

A hash-set analogue that does not own its data.

It can be used to “mark” items without the need to transfer ownership to the map

Example use case

/// Process arguments while ignoring duplicates
fn process_args(args: impl IntoIterator<Item=String>) {
  let mut same=  HashRefSet::new();
  for argument in args.into_iter()
  {
    if !same.insert(argument.as_str()) {
      // Already processed this input, ignore
      continue;
    }
    //do work...
  }
}

Serialisation support with serde crate

HashRefSet and HashType both implement Serialize and Deserialize from the serde crate if the serde feature is enabled. By default it is not.

Drawbacks

Since the item is not inserted itself, we cannot use Eq to double check there was not a hash collision. While the hashing algorithm used (Sha512) is extremely unlikely to produce collisions, especially for small data types, keep in mind that it is not infallible.

Structs

HashRefSet

A hash-set of references to an item.

Type Aliases

HashType

The type used to store the hash of each item.