1 files changed, 27 insertions, 0 deletions
diff --git a/tests/weight.ml b/tests/weight.ml
new file mode 100644
index 0000000..33eb9b1
--- /dev/null
+++ b/tests/weight.ml
@@ -0,0 +1,27 @@
+type expr =
+  | EConst of int
+  | EAdd of expr * expr
+  [@@deriving visitors { variety = "iter" }]
+
+let weight (e : expr) : int =
+(* return the weight of an expr, where the weight of constants is its *)
+(* value, and additions have weight 5.                                *)
+  let v = object
+    val mutable weight = 0
+    method weight = weight
+    inherit [_] iter as super
+    method! visit_EAdd env e0 e1 =
+      weight <- weight + 5;
+      super#visit_EAdd env e0 e1
+    method! visit_EConst env i =
+      weight <- weight + i;
+      super#visit_EConst env i
+    end in
+  v#visit_expr () e;
+  v#weight
+;;
+
+let c = EConst 2 in
+    let e = EAdd(c,EAdd(c,c)) in
+    print_int (weight e)
+;;