🔢 Rust Enums §

Types §

“Normal” enums: §

• Can hold enum values
  • (start at 0 without specification)
• Can be compared (via derive)
• Can have methods, like structs

Example: §

#[derive(Copy, Clone, Debug, PartialEq, Eq)]
enum Measure {
	Meter = 1, //optional val
	Centimeter = 2
}

// usage
Measure::Meter

Enums with data: §

Mirroring struct types:

• tuple variants accept arguments (like 🔢 Rust Tuple-Like Structs)
  • e.g.: x(T, V) → tuple variant x, taking arguments of Type T, V
• struct variants can contain named fields (like 🏷️ Rust Named-Fields Structs)
  • e.g.: x { t: T, v: V} → struct variant x, taking arguments t, v of Type T, V
• unit variants are fields without data (like 🍽️ Rust Unit-Like Structs)
  • e.g.: x → unit variant x

Converting §

• Enum to value: cast
• Value to enum: checked cast, or enum_primitive crate

Use case §

• simplicity
• no change in the datastructure is expected
  • → use struct with 👨‍🚀 Rust Traits instead