blob: 1f602f9a5388702398e9102519e74dd656582a04 (
plain) (
tree)
|
|
package magnolia.examples
import scala.language.existentials
import scala.language.higherKinds
import magnolia._
import scala.language.experimental.macros
trait Default[T] { def default: T }
object Default {
type Typeclass[T] = Default[T]
def join[T](ctx: JoinContext[Default, T]): Default[T] = new Default[T] {
def default = ctx.construct { param => param.typeclass.default }
}
def dispatch[T](ctx: DispatchContext[Default, T])(): Default[T] = new Default[T] {
def default: T = ctx.subtypes.head.typeclass.default
}
implicit val string: Default[String] = new Default[String] { def default = "" }
implicit val int: Default[Int] = new Default[Int] { def default = 0 }
implicit def generic[T]: Default[T] = macro Magnolia.generic[T]
}
|