Add test

Author: odersky

tests/run/fragables-extension.scala

@@ -0,0 +1,28 @@
+trait Frag
+
+case class IntFrag(x: Int) extends Frag
+case class StringFrag(x: String) extends Frag
+
+trait Fragable[T]:
+  extension (x: T)
+    def toFrags: List[Frag]
+
+given Fragable[Int] =
+  x => List(IntFrag(x))
+given Fragable[String] =
+  x => List(StringFrag(x))
+given [A: Fragable] as Fragable[List[A]] =
+  x => x.flatMap(_.toFrags)
+given Fragable[EmptyTuple] =
+  x => Nil
+given [A: Fragable, B <: Tuple: Fragable] as Fragable[A *: B] =
+  x => x.head.toFrags ++ x.tail.toFrags
+
+def f[T: Fragable](x: T) =
+  println(s"got: ${x.toFrags.mkString(", ")}")
+
+@main def Test =
+  f(1)
+  f("abc")
+  f(List(1, 2, 3))
+  f(1, "a", List("c", "d"))