Scala 案例类与 Kotlin 数据类

Question

Scala has a feature called case class , while Kotlin has another feature called data class . Which are the main differences between Scala case class and Kotlin data class ?

Answer 1

Overall they are very similar, but there are some differences I'd mention:

1. Scala case class can have multiple parameter lists (including implicit parameters), and only parameters from the first list are used for toString / equals / hashCode .

2. Scala allows a case class to have no parameters, Kotlin doesn't. Of course, usually such a case class should be an object instead.

3. On that note, case object s exist.

4. The companion object of a case class extends the corresponding function type by default.

Answer 2

Scala case class creates a class which:

1. Defines accessor functions (getters and setters basically)
2. Overrides naturally hashcode , toString and equals functions
3. Provides a copy function in order to create in an easy way shallow copies.

Kotlin data class does pretty much the same thing as Scala case class :

1. Defines accessor functions (getters and setters basically)

2. Overrides naturally hashcode , toString and equals functions

3. Provides a copy function in order to create in an easy way shallow copies.

The main differences between the two is the fact that Scala provides a more powerful pattern matching feature compared to Kotlin (in fact Kotlin doesn't have real pattern matching).