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Diffstat (limited to 'test/files/run/gadts.scala')
-rwxr-xr-x | test/files/run/gadts.scala | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/test/files/run/gadts.scala b/test/files/run/gadts.scala new file mode 100755 index 0000000000..36d6fc9530 --- /dev/null +++ b/test/files/run/gadts.scala @@ -0,0 +1,19 @@ +abstract class Term[T]; +case class Lit(x: int) extends Term[int]; +case class Succ(t: Term[int]) extends Term[int]; +case class IsZero(t: Term[int]) extends Term[boolean]; +case class If[T](c: Term[boolean], + t1: Term[T], + t2: Term[T]) extends Term[T]; + +object Test extends Application { + def eval[T](t: Term[T]): T = t match { + case Lit(n) => n + case Succ(u) => eval(u) + 1 + case IsZero(u) => eval(u) == 0 + case If(c, u1, u2) => eval(if (eval(c)) u1 else u2) + } + Console.println( + eval(If(IsZero(Lit(1)), Lit(41), Succ(Lit(41))))) +} + |