Add option --only-matching to limit output

bin/main.ml

@@ -46,11 +46,24 @@ let main =
   let doc = "Generate an ATD file from a list of JSON Schema / OpenAPI document" in
   let state_term =
     Term.(
-      const (fun skip_doc pad ->
-        Generator.{ with_doc = not skip_doc; protect_against_duplicates = (if pad then Some (ref []) else None) }
+      const (fun skip_doc pad toplevel_types ->
+        Generator.
+          {
+            with_doc = not skip_doc;
+            protect_against_duplicates = (if pad then Some (ref []) else None);
+            toplevel_types;
+          }
       )
       $ Arg.(value (flag (info [ "skip-doc" ] ~doc:"Skip documentation annotations.")))
       $ Arg.(value (flag (info [ "protect-against-duplicates" ] ~doc:"Make sure no duplicate types are generated.")))
+      $ (const (function
+           | [] -> `All
+           | some -> `Only some
+           )
+        $ Arg.(
+            value (opt_all string [] (info [ "only-matching" ] ~docv:"REGEXP" ~doc:"Only output types matching REGEXP."))
+          )
+        )
     )
   in
   let paths = Arg.(non_empty & pos_all file [] & info [] ~docv:"FILES" ~doc) in

lib/generator.ml

@@ -5,9 +5,10 @@ open Utils
 type state = {
   with_doc : bool;
   protect_against_duplicates : string list ref option;
+  toplevel_types : [ `All | `Only of string list ];
 }
 
-let default_state = { with_doc = true; protect_against_duplicates = None }
+let default_state = { with_doc = true; protect_against_duplicates = None; toplevel_types = `All }
 
 let record_field_name _state str =
   let cleaned_field_name = Utils.sanitize_name str in
@@ -288,6 +289,13 @@ type int64 = int <ocaml repr="int64">
     from
 
 let make_atd_of_schemas state schemas =
+  let schemas =
+    match state.toplevel_types with
+    | `All -> schemas
+    | `Only l ->
+      let res = List.map (Printf.ksprintf Str.regexp "^%s$") l in
+      List.filter (fun (name, _) -> List.exists (fun re -> Str.string_match re name 0) res) schemas
+  in
   input_toplevel_schemas :=
     List.filter_map
       (function