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package magnolia.examples
import scala.language.higherKinds
import magnolia._
import scala.language.experimental.macros
trait Eq[T] { def equal(value: T, value2: T): Boolean }
object Eq {
type Typeclass[T] = Eq[T]
def combine[T](ctx: CaseClass[Eq, T]): Eq[T] = new Eq[T] {
def equal(value1: T, value2: T) =
ctx.parameters.forall { param => param.typeclass.equal(param.dereference(value1), param.dereference(value2)) }
}
def dispatch[T](ctx: SealedTrait[Eq, T]): Eq[T] = new Eq[T] {
def equal(value1: T, value2: T): Boolean =
ctx.dispatch(value1) { case sub => sub.typeclass.equal(sub.cast(value1), sub.cast(value2)) }
}
implicit val string: Eq[String] = new Eq[String] { def equal(v1: String, v2: String) = v1 == v2 }
implicit val int: Eq[Int] = new Eq[Int] { def equal(v1: Int, v2: Int) = v1 == v2 }
implicit def gen[T]: Eq[T] = macro Magnolia.gen[T]
}
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