Enumeratum module

kantan.csv comes with an enumeratum module that can be used by adding the following dependency to your build.sbt:

libraryDependencies += "com.nrinaudo" %% "kantan.csv-enumeratum" % "0.7.0"

Name-based enumerations

When working with enumerations of type Enum, you should import the following package:

import kantan.csv.enumeratum._

And that’s pretty much it. You can now encode and decode your enumeration directly.

Let’s first set our types up:

import enumeratum._

sealed trait DummyEnum extends EnumEntry

object DummyEnum extends Enum[DummyEnum] {

  val values = findValues

  case object Hello   extends DummyEnum
  case object GoodBye extends DummyEnum
  case object Hi      extends DummyEnum

}

And a few further imports, to bring our enumeration and the kantan.csv syntax in scope:

import kantan.csv.rfc
import kantan.csv.ops._

We can then simply write the following:

"Hello,GoodBye".readCsv[List, List[DummyEnum]](rfc)
// res0: List[kantan.csv.package.ReadResult[List[DummyEnum]]] = List(
//   Right(value = List(Hello, GoodBye))
// )

"Hello,GoodDay".readCsv[List, List[DummyEnum]](rfc)
// res1: List[kantan.csv.package.ReadResult[List[DummyEnum]]] = List(
//   Left(
//     value = TypeError(
//       message = "'GoodDay' is not a member of enumeration [Hello, GoodBye, Hi]"
//     )
//   )
// )

Value-based enumerations

For enumerations of type ValueEnum, you should import the following package:

import kantan.csv.enumeratum.values._

And that’s pretty much it. You can now encode and decode your enumeration directly.

Let’s first set our types up:

import enumeratum.values._

sealed abstract class Greeting(val value: Int) extends IntEnumEntry

object Greeting extends IntEnum[Greeting] {

  val values = findValues

  case object Hello   extends Greeting(1)
  case object GoodBye extends Greeting(2)
  case object Hi      extends Greeting(3)
  case object Bye     extends Greeting(4)

}

And a few further imports, to bring our enumeration and the kantan.csv syntax in scope:

import kantan.csv.rfc
import kantan.csv.ops._

We can then simply write the following:

"1,2".readCsv[List, List[Greeting]](rfc)
// res3: List[kantan.csv.package.ReadResult[List[Greeting]]] = List(
//   Right(value = List(Hello, GoodBye))
// )

"1,-2".readCsv[List, List[Greeting]](rfc)
// res4: List[kantan.csv.package.ReadResult[List[Greeting]]] = List(
//   Left(value = TypeError(message = "'-2' is not in values [1, 2, 3, 4]"))
// )
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