Crate big_enum_set

A library for creating enum sets that are stored as compact bit sets. The code is based on the enumset crate, except that the backing store used is an array of usize. This enables use with enums with large number of variants. The API is very similar to that of enumset.

For serde support, enable the serde feature.

Defining enums for use with BigEnumSet

Enums to be used with BigEnumSet should be defined using #[derive(BigEnumSetType)]:

#[derive(BigEnumSetType, Debug)]
pub enum Enum {
   A, B, C, D, E, F, G,
}

For more information on more advanced use cases, see the documentation for BigEnumSetType.

Working with BigEnumSets

BigEnumSets can be constructed via BigEnumSet::new() like a normal set. In addition, #[derive(BigEnumSetType)] creates operator overloads that allow you to create BigEnumSets like so:

let new_set = Enum::A | Enum::C | Enum::G;
assert_eq!(new_set.len(), 3);

All bitwise operations you would expect to work on bitsets also work on both BigEnumSets and enums with #[derive(BigEnumSetType)]:

// Intersection of sets
assert_eq!((Enum::A | Enum::B) & Enum::C, BigEnumSet::empty());
assert_eq!((Enum::A | Enum::B) & Enum::A, Enum::A);
assert_eq!(Enum::A & Enum::B, BigEnumSet::empty());

// Symmetric difference of sets
assert_eq!((Enum::A | Enum::B) ^ (Enum::B | Enum::C), Enum::A | Enum::C);
assert_eq!(Enum::A ^ Enum::C, Enum::A | Enum::C);

// Difference of sets
assert_eq!((Enum::A | Enum::B | Enum::C) - Enum::B, Enum::A | Enum::C);

// Complement of sets
assert_eq!(!(Enum::E | Enum::G), Enum::A | Enum::B | Enum::C | Enum::D | Enum::F);

The big_enum_set! macro allows you to create BigEnumSets in constant contexts:

const CONST_SET: BigEnumSet<Enum> = big_enum_set!(Enum::A | Enum::B);
assert_eq!(CONST_SET, Enum::A | Enum::B);

Mutable operations on the BigEnumSet work similarly to Rust’s builtin sets:

let mut set = BigEnumSet::new();
set.insert(Enum::A);
set.insert_all(Enum::E | Enum::G);
assert!(set.contains(Enum::A));
assert!(!set.contains(Enum::B));
assert_eq!(set, Enum::A | Enum::E | Enum::G);

Macros

• big_enum_set
  Creates a BigEnumSet literal, which can be used in const contexts.

Structs

• BigEnumSet
  An efficient set type for enums.
• EnumSetIter
  The iterator used by BigEnumSets.

Traits

• BigEnumSetType
  The trait used to define enum types that may be used with BigEnumSet.

Derive Macros

• BigEnumSetType
  Procedural derive generating impls for big_enum_set::BigEnumSetType and associated traits.