From ed9925e32d5303b33cead40c703855e07b87fb78 Mon Sep 17 00:00:00 2001
From: Sebastien Mondet <sebastien.mondet@ahrefs.com>
Date: Wed, 4 Dec 2024 14:22:02 -0500
Subject: [PATCH] Make `from` Vs `module` keyword also parametrizable

---
 bin/main.ml      |  7 +++++--
 lib/generator.ml | 15 ++++++++++-----
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/bin/main.ml b/bin/main.ml
index 2273e02..91773df 100644
--- a/bin/main.ml
+++ b/bin/main.ml
@@ -68,9 +68,12 @@ let main =
         )
       $ Arg.(value (flag (info [ "avoid-dangling-refs" ] ~doc:"Convert dangling refs to json.")))
       $ Arg.(
+          let keyword = enum [ "module", `Module; "from", `From ] in
           value
-            (opt (pair ~sep:':' string string) Generator.default_state.json_ocaml_type
-               (info [ "json-ocaml-type" ] ~docv:"MODULE.PATH:TYPE-NAME" ~doc:"Use an alternate Mod.type for `json`.")
+            (opt (t3 ~sep:':' keyword string string) Generator.default_state.json_ocaml_type
+               (info [ "json-ocaml-type" ] ~docv:"KEYWORD:MODULE.PATH:TYPE-NAME"
+                  ~doc:"Use an alternate Mod.type for `json`, e.g. from:My_mod.Submod:json_type."
+               )
             )
         )
     )
diff --git a/lib/generator.ml b/lib/generator.ml
index 7b596a3..7f85dcb 100644
--- a/lib/generator.ml
+++ b/lib/generator.ml
@@ -7,7 +7,7 @@ type state = {
   protect_against_duplicates : string list ref option;
   toplevel_types : [ `All | `Only of string list ];
   avoid_dangling_refs : bool;
-  json_ocaml_type : string * string;
+  json_ocaml_type : [ `From | `Module ] * string * string;
 }
 
 let default_state =
@@ -16,7 +16,7 @@ let default_state =
     protect_against_duplicates = None;
     toplevel_types = `All;
     avoid_dangling_refs = false;
-    json_ocaml_type = "Yojson.Basic", "t";
+    json_ocaml_type = `Module, "Yojson.Basic", "t";
   }
 
 let record_field_name _state str =
@@ -297,13 +297,18 @@ let process_schemas state (schemas : (string * schema or_ref) list) =
     [] schemas
 
 let base state from =
-  let module_path, type_t = state.json_ocaml_type in
+  let keyword, module_path, type_t = state.json_ocaml_type in
   sprintf
     {|(* Generated by jsonschema2atd from %s *)
-type json <ocaml module="%s" t="%s"> = abstract
+type json <ocaml %s="%s" t="%s"> = abstract
 type int64 = int <ocaml repr="int64">
 |}
-    from module_path type_t
+    from
+    ( match keyword with
+    | `From -> "from"
+    | `Module -> "module"
+    )
+    module_path type_t
 
 let make_atd_of_schemas state schemas =
   let schemas =