| name | scala-213-type-hierarchy-and-modeling |
| description | Define idiomatic Scala 2.13 type hierarchies and domain models, replacing Python's class structures and Enums with traits and case classes. |
Sealed Traits and Case Objects for Enums
Scala 2.13 does not support the enum keyword. To represent a fixed set of types (like TokenType):
- Define a
sealed trait as the base type.
- Define
case object instances for each specific type.
This ensures exhaustiveness checking during pattern matching.
Class Hierarchies
Replace Python base classes with a sealed trait or abstract class for the BaseTokenizer.
- Use a
trait if you only define an interface.
- Use an
abstract class if you need to provide common constructor parameters or shared logic for all tokenizers.
Data Representation
Use case class for the Token model. Case classes provide:
- Immutability by default.
- Built-in
equals, hashCode, and toString.
- A
.copy() method, which is essential for the withMetadata pattern.
The withMetadata Pattern
To implement withMetadata idiomatically, leverage the .copy() method of the Token case class. This allows you to return a new instance with updated fields without mutating the original object, maintaining functional purity.
