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November 26, 2024 11:20
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How to repack arbitrary tuple of Eithers into a case class
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import java.util.UUID | |
import java.time.Instant | |
import scala.deriving.Mirror | |
case class MyCaseClass( | |
intField: Int, | |
longField: Long, | |
doubleField: Double, | |
stringField: String, | |
booleanField: Boolean, | |
charField: Char, | |
floatField: Float, | |
byteField: Byte, | |
shortField: Short, | |
uuidField: UUID, | |
instantField: Instant, | |
bigDecimalField: BigDecimal, | |
bigIntField: BigInt, | |
optionField: Option[String], | |
listField: List[Int], | |
setField: Set[Double], | |
mapField: Map[String, Int], | |
vectorField: Vector[Char], | |
arrayField: Array[Byte], | |
eitherField: Either[String, Int], | |
tupleField: (String, Int), | |
seqField: Seq[Double], | |
iterableField: Iterable[Boolean], | |
stringBuilderField: StringBuilder, | |
symbolField: Symbol | |
) | |
import java.util.UUID | |
import java.time.Instant | |
val allRights: ( | |
Either[String, Int], | |
Either[String, Long], | |
Either[String, Double], | |
Either[String, String], | |
Either[String, Boolean], | |
Either[String, Char], | |
Either[String, Float], | |
Either[String, Byte], | |
Either[String, Short], | |
Either[String, UUID], | |
Either[String, Instant], | |
Either[String, BigDecimal], | |
Either[String, BigInt], | |
Either[String, Option[String]], | |
Either[String, List[Int]], | |
Either[String, Set[Double]], | |
Either[String, Map[String, Int]], | |
Either[String, Vector[Char]], | |
Either[String, Array[Byte]], | |
Either[String, Either[String, Int]], | |
Either[String, (String, Int)], | |
Either[String, Seq[Double]], | |
Either[String, Iterable[Boolean]], | |
Either[String, StringBuilder], | |
Either[String, Symbol] | |
) = ( | |
Right(42), | |
Right(123456789L), | |
Right(3.14), | |
Right("Scala 3"), | |
Right(true), | |
Right('A'), | |
Right(2.71f), | |
Right(127.toByte), | |
Right(32767.toShort), | |
Right(UUID.randomUUID()), | |
Right(Instant.now()), | |
Right(BigDecimal(12345.6789)), | |
Right(BigInt(987654321)), | |
Right(Some("Option Value")), | |
Right(List(1, 2, 3)), | |
Right(Set(1.1, 2.2, 3.3)), | |
Right(Map("key1" -> 1, "key2" -> 2)), | |
Right(Vector('x', 'y', 'z')), | |
Right(Array(1.toByte, 2.toByte, 3.toByte)), | |
Right(Right(99)), | |
Right(("tupleValue", 123)), | |
Right(Seq(1.0, 2.0, 3.0)), | |
Right(Iterable(true, false, true)), | |
Right(new StringBuilder("StringBuilder Value")), | |
Right(Symbol("symbolValue")) | |
) | |
val someLefts: ( | |
Either[String, Int], | |
Either[String, Long], | |
Either[String, Double], | |
Either[String, String], | |
Either[String, Boolean], | |
Either[String, Char], | |
Either[String, Float], | |
Either[String, Byte], | |
Either[String, Short], | |
Either[String, UUID], | |
Either[String, Instant], | |
Either[String, BigDecimal], | |
Either[String, BigInt], | |
Either[String, Option[String]], | |
Either[String, List[Int]], | |
Either[String, Set[Double]], | |
Either[String, Map[String, Int]], | |
Either[String, Vector[Char]], | |
Either[String, Array[Byte]], | |
Either[String, Either[String, Int]], | |
Either[String, (String, Int)], | |
Either[String, Seq[Double]], | |
Either[String, Iterable[Boolean]], | |
Either[String, StringBuilder], | |
Either[String, Symbol] | |
) = ( | |
Left("Invalid Int"), | |
Right(123456789L), | |
Left("Invalid Double"), | |
Right("Scala 3"), | |
Left("Invalid Boolean"), | |
Right('A'), | |
Left("Invalid Float"), | |
Right(127.toByte), | |
Right(32767.toShort), | |
Left("Invalid UUID"), | |
Right(Instant.now()), | |
Left("Invalid BigDecimal"), | |
Right(BigInt(987654321)), | |
Left("Invalid Option"), | |
Right(List(1, 2, 3)), | |
Left("Invalid Set"), | |
Right(Map("key1" -> 1, "key2" -> 2)), | |
Left("Invalid Vector"), | |
Right(Array(1.toByte, 2.toByte, 3.toByte)), | |
Left("Invalid Either"), | |
Right(("tupleValue", 123)), | |
Left("Invalid Seq"), | |
Right(Iterable(true, false, true)), | |
Left("Invalid StringBuilder"), | |
Right(Symbol("symbolValue")) | |
) | |
import scala.compiletime.{erasedValue, summonInline, constValueTuple, error} | |
import scala.deriving.Mirror | |
def extractRights[T <: Tuple](tuple: T): Array[Any] = | |
def process(tuple: Tuple): List[Any] = tuple match | |
case EmptyTuple => Nil | |
case head *: tail => | |
head match | |
case Right(value) => value :: process(tail) | |
case Left(error) => | |
throw IllegalArgumentException(s"Found a Left: $error") | |
process(tuple).toArray | |
// Define a type-level operation to extract the right-hand type from Either | |
type UnwrapEither[T] = T match | |
case Either[_, r] => r | |
inline def unpackAndConstruct[A <: Product, T <: Tuple]( | |
values: T | |
): Either[String, A] = | |
inline summonInline[Mirror.ProductOf[A]] match | |
case m: Mirror.ProductOf[A] => | |
type CaseClassFieldTypes = m.MirroredElemTypes | |
type UnwrappedTupleTypes = Tuple.Map[T, UnwrapEither] | |
inline erasedValue[CaseClassFieldTypes] match | |
case _: UnwrappedTupleTypes => | |
try | |
val args = extractRights(values) | |
Right(m.fromProduct(Tuple.fromArray(args))) | |
catch case e: IllegalArgumentException => Left(e.getMessage) | |
case _ => error("Provided tuple does not match the case class") | |
@main def main = | |
println(unpackAndConstruct[MyCaseClass, allRights.type](allRights)) | |
println(unpackAndConstruct[MyCaseClass, someLefts.type](someLefts)) |
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