Version 0.3

Q: How to use the Enum type?

A: EEnum types are automatically encoded/decoded using Codec.derivedEnum.

Enum types are automatically encoded/decoded using Codec.derivedEnum. The following example defines an Enum type named Color and encodes/decodes it using Codec.derivedEnum.

The Enum type treats the value of the Enum as it is as a string. For example, Color.Red is treated as “Red”. This can be used with MySQL's Enum type.

Example:

import ldbc.codec.*

enum Color:
  case Red, Blue, Yellow
object Color:
  given Codec[Color] = Codec.derivedEnum[Color]

val query = sql"SELECT 'Red'".query[Color].to[Option]

If you want to encode/decode an Enum using the values of the fields it contains instead of strings, you need to extend Codec to implement it. The following example defines an Enum type called Color and extends Codec to encode/decode it.

import ldbc.codec.*

enum Color(val colorCode: String):
  case Red extends Color("FF0000")
  case Blue extends Color("0000FF")
  case Yellow extends Color("FFFF00")
object Color:
  given Codec[Color] = Codec[String].eimap { str =>
    Color.values.find(_.colorCode == str) match
      case Some(color) => Right(color)
      case None        => Left(s"Invalid color code: $str")
  } (_.colorCode)

val query = sql"SELECT 'FF0000'".query[Color].to[Option]

References