10.7 Limitations and Considerations
10.7.1 Extending Enums
Enums defined in a library module cannot be extended with new variants from other modules.
- Closed Set: The set of variants is fixed at definition.
- Workarounds: Use traits or other patterns if extensibility is required.
10.7.2 Matching on Enums
When pattern matching, Rust requires handling all possible variants unless you use a wildcard _.
- Exhaustiveness: Ensures that all cases are considered.
- Order Matters: Patterns are checked from top to bottom, and the first match is selected.
- Default Cases: Use
_ => { }to handle unspecified variants.
10.7.3 Pattern Matching Details
- Pattern Matching: A powerful feature in Rust, allowing for expressive and concise code.
- Complex Patterns: You can match on nested data, use guards, and destructure complex types.
- Further Exploration: We'll discuss pattern matching in much more detail in a later chapter.