run2-scala-idiomatic-patterns

name	run2_scala-idiomatic-patterns
description	Idiomatic Scala patterns for translating Python code including enums, case classes, and naming conventions.

Idiomatic Scala Patterns

Enums (Scala 2.13)

Use sealed abstract class with companion object containing case objects:

sealed abstract class TokenType(val value: String)
object TokenType {
  case object STRING extends TokenType("string")
}

Case Classes for Immutable Data

• Python @dataclass(frozen=True) -> Scala case class
• Use copy() for creating modified instances
• Default params replace field(default_factory=...)

Naming Conventions

• camelCase for methods/fields: tokenize_batch -> tokenizeBatch
• PascalCase for types: same in both languages
• Avoid _ prefix for private fields; use private modifier

Avoid var and return

• Use Option chains, match, and foldLeft instead of mutable vars
• Use expression-oriented style: every block returns a value
• Prefer val over var wherever possible

Pattern Matching over isinstance

Python isinstance(value, (str, bytes)) becomes Scala pattern matching:

value match {
  case s: String => ...
  case d: Double => ...
}