Print derivers as well as registered transformations

Signed-off-by: Rudi Grinberg <[email protected]>

ocaml-migrate-parsetree.opam

@@ -15,6 +15,7 @@ build: [
 ]
 depends: [
   "result"
+  "ppx_derivers"
   "dune" {build}
 ]
 available: ocaml-version >= "4.02.0"

src/jbuild

@@ -4,7 +4,7 @@
  ((name migrate_parsetree)
   (public_name ocaml-migrate-parsetree)
   (wrapped false)
-  (libraries (compiler-libs.common result))
+  (libraries (compiler-libs.common result ppx_derivers))
   (flags (:standard -open Result))
   (modules (:standard \ migrate_parsetree_driver_main))
   (preprocess (action (run ${exe:../tools/pp.exe} ${read:ast-version} ${<})))

src/migrate_parsetree_driver.ml

@@ -434,10 +434,20 @@ let process_file ~config ~output ~output_mode ~embed_errors file =
     ()
 
 let print_transformations () =
+  let print_group name = function
+    | [] -> ()
+    | names ->
+        Printf.printf "%s:\n" name;
+        List.iter (Printf.printf "%s\n") names
+  in
   all_rewriters ()
-  |> List.iter (fun r ->
-      rewriter_group_names r
-      |> List.iter (Printf.printf "%s\n"))
+  |> List.map rewriter_group_names
+  |> List.concat
+  |> print_group "Registered Transformations";
+  Ppx_derivers.derivers ()
+  |> List.map (fun (x, _) -> x)
+  |> print_group "Registered Derivers"
+
 
 let run_as_standalone_driver () =
   let request_print_transformations = ref false in