Given a type which has a "converter", I would like to have automatic conversion on method call using this type's companion object. That is, given the following definition,
case class Converted(name: String)
trait Converter[A] {
def perform: Converted
}
implicit val StringConverter = new Converter[String] {
def perform = Converted("String")
}
make the following code to work:
implicit def toConverter(a: String.type): Converted =
implicitly[Converter[String]].perform // Error: `Found String.type, required AnyRef`
def f(needsConverted: Converted) = ???
f(String) // <- That's what I would like to be able to write.
But this fails and both attempts for conversion fail. Note that I cannot change f because it is provided by a third-party library and there are many of them.
f(String) compile using implicits?If not possible for Strings, what about classes which do have a companion object, can I do this generically like:
object TheClass
case class TheClass()
implicit val TheClassConverter = new Converter[TheClass] {
def perform = Converted("TheClass")
}
implicit def toConverter[A: Converter](a: A.type): Converted =
implicitly[Converter[A]].perform // Error: `Not found value A`
implicit def toConverter(a: TheClass.type): Converted =
implicitly[Converter[TheClass]].perform // This works but is not generic
f(TheClass) // This works.
toConverter to compile ?Instead of defining an implicit instance for the type MyClass you can define an implicit instance for the companion type MyClass.type.
implicit val TheClassConverter: Converter[MyClass.type] = new Converted[MyClass.type] {
def perform = Converted("MyClass")
}