phaylon / flagnum

Groupable sets of unit-only enums based on a bitset implementation

Groupable sets of unit-only enums based on a bitset implementation.

Description

• Transforms Rust enums and generates corresponding set types, so the set types can be extended with associated items and have foreign traits implemented on it.
• Allows grouping of variants into a constant set via the groups attributes.
• Provides a set API via the Flags trait, allowing generic operations on sets and items.
• Automatically chooses the smallest possible represenation given the number of variants.
• Allows adding attributes and documentation to the generated set type and group constants.
• Comes with a set oriented serde implementation, available via the serde feature. The set type serializes and deserializes like a sequence of values belonging to the set.
• Auto-implements a number of standard library traits for enums and set types.
• Uses the enum discriminant value to store the set bit information.

Example

#[flagnum::flag(
    #[derive(Default)] pub MySet,
    groups(pub GROUP_1, pub GROUP_2),
)]
pub enum MyItem {
    ItemA,
    #[groups(GROUP_1)]
    ItemB,
    #[groups(GROUP_1, GROUP_2)]
    ItemC,
}

use flagnum::Flags;
assert!(! MySet::GROUP_1.contains(MyItem::ItemA));
assert!(MySet::GROUP_1.contains(MyItem::ItemB));
assert!(MySet::GROUP_1.contains(MySet::GROUP_2));