Support source-first setters and configurable updater arguments

record.ml

@@ -95,3 +95,24 @@ let () =
   assert (Verbs.read_colour (Verbs.replace_colour "blue" original) = "blue");
   assert (Verbs.read_colour (Verbs.revise_colour ~f:(fun s -> s ^ "s") original) = "greys");
   assert (Fieldglass.view Verbs._colour original = "grey")
+
+module Ordered = struct
+  type t = { count : int }
+    [@@fieldglass generate ~self_arg_first ~func_named_arg:change]
+end
+
+module Positional = struct
+  type t = { count : int }
+    [@@fieldglass generate ~self_arg_first ~func_no_named_arg]
+end
+
+module Last = struct
+  type t = { count : int } [@@fieldglass generate ~func_no_named_arg]
+end
+
+let () =
+  assert (Ordered.set_count Ordered.{ count = 1 } 2 = Ordered.{ count = 2 });
+  assert (Ordered.update_count Ordered.{ count = 1 } ~change:succ = Ordered.{ count = 2 });
+  assert (Fieldglass.set Ordered._count 2 Ordered.{ count = 1 } = Ordered.{ count = 2 });
+  assert (Positional.update_count Positional.{ count = 1 } succ = Positional.{ count = 2 });
+  assert (Last.update_count succ Last.{ count = 1 } = Last.{ count = 2 })