README

samples for demonstrating how implicits are searched.

implicit_def.scala

package object lib {
  implicit def f2bp(f: Foo) = Bar("package object")
}
package lib {
  case class Foo()
  case class Bar(x: String)

  object Foo {
//    implicit def f(f: Foo) = Bar("Foo")
  }
  object Bar {
//    implicit def f(f: Foo) = Bar("Bar")
  }
}

package user {

  import lib.{Foo, Bar}

  object X {

    //implicit def f2b0(f: Foo) = Bar("implicit def")
    //implicit val f2b1 : Foo => Bar = _ => Bar("implicit val")

    def main(arg: Array[String]): Unit = {
      implicit def f2b(f: Foo) = Bar("local")

      println((Foo()):Bar)
    }
  }
}

implicit_val.scala

package object lib {
//  implicit val p: Foo = Foo("package object lib")
}

package lib {
  case class Foo(x: String)
  object Foo {
    implicit val foo: Foo = Foo("package lib")
    def f(implicit i: Foo) = println(i)   
  }
}

package user {
  import lib.Foo
  import lib.Foo.f

  trait XX {
    implicit val xx: Foo = Foo("XX")
  }

  object X extends XX {

    //implicit override val xx: Foo = Foo("X toplevel override")
    //implicit val toplevel: Foo = Foo("X toplevel")

    def main(arg: Array[String]): Unit = {
      //implicit val x = Foo("local")
      //import Y.y 
      //import Z._
      f
    }
  }
/*
  object Y {
    implicit val y: Foo = Foo("Y")
  }
  object Z {
    implicit val z: Foo = Foo("Z")
  }
*/
/*
  object XXX {
    def main(arg: Array[String]): Unit = {
      f
    }
  }
*/
}

implicit_val2.scala

package object user {
  import lib.Foo
  implicit val from_package = Foo("package object user")
}

implicit_val3.scala

package lib {
  class Boo
  object Boo{
    implicit val g: Foo[Bar] = Foo(Bar("Boo"))
  }
  case class Foo[X](x: X) extends Boo
  case class Bar(x: String)

  object Bar {
//    implicit val f1: Foo[Bar] = Foo(Bar("Bar"))
  }
  object Foo {
//    implicit val f0: Foo[Bar] = Foo(Bar("Foo"))
  }
  object F {
    def f(implicit i: Foo[Bar]) = println(i)
  }
}

package user {
  import lib.F.f
  import lib.{Foo, Bar}

  object X {
    def main(arg: Array[String]) = {
//      implicit val local: Foo[Bar] = Foo(Bar("local"))
      f
    }
  }
}

package_mixins_conflict_resolution.scala

package lib {
  trait MyImplicits {
    implicit def string2int(x: String) = x.toInt
  }
}

package object user extends lib.MyImplicits {}

package user {
  object Test {
    implicit def string2int = null
//    implicit def string2intX(x: String) = ("6").toInt
    def x: Int = "5"
    def main(arg: Array[String]) = println(x)
  }
}

typeclass_implicit.scala

package lib {

  trait ExecutionStrategy {
    def exec: Unit
  }

  object ExecutionStrategy {
    implicit object f extends ExecutionStrategy {
      def exec = println("object ExecutionStrategy")
    }
  }

  object F {
    def f(implicit f: ExecutionStrategy) = f.exec
  }
}

package user {
  import lib.F.f
  import lib.ExecutionStrategy

  object X {
    implicit val toplevel = new ExecutionStrategy {
      def exec = println("X toplevel")
    }
  
    def main(arg: Array[String]): Unit = {
      implicit val local = new ExecutionStrategy {
        def exec = println("local")
      }
      f
    }
  } 
}

typeclass_implicit2.scala

package lib {

  class Foo
  class Bar
  
  trait ExecutionStrategy[X] {
    def exec: Unit
  }

  object ExecutionStrategy {
    implicit object foo extends ExecutionStrategy[Foo] {
      def exec = println("Foo")
    }
/*
    implicit object bar extends ExecutionStrategy[Bar] {
      def exec = println("Bar")
    }
*/
  }

  object Bar {
    implicit object f extends ExecutionStrategy[Bar] {
      def exec = println("Bar2")
    }
  }

  object F {
    def f[X](implicit e: ExecutionStrategy[X]) = e.exec
  }
}

package user {
  import lib.F.f
  import lib.{ExecutionStrategy, Foo, Bar}

  object X {

    implicit val toplevel = new ExecutionStrategy[Foo] {
      def exec = println("Y toplevel")
    }
  
    def main(arg: Array[String]): Unit = {
      implicit val local = new ExecutionStrategy[Foo] {
        def exec = println("local")
      }

      f[Foo]
      f[Bar]
    }
  }  
}