umm working?

belt/dune

@@ -1,2 +1,5 @@
+(include_subdirs unqualified)
+
 (library
+(c_names stubs)
   (name Belt))

belt/stubs.c

@@ -0,0 +1,12 @@
+#include <caml/mlvalues.h>
+#include <caml/alloc.h>
+#include <caml/memory.h>
+
+CAMLprim value belt_makemutablelist(value a, value l) {
+  CAMLparam2(a, l);
+  CAMLlocal1(box);
+  box = caml_alloc_small(2, 0);
+  Field(box, 0) = a;
+  Field(box, 1) = l;
+  CAMLreturn(box);
+}

belt_ppx/Belt_ppx.ml

@@ -11,23 +11,22 @@ let mapper =
       let loc = e.pexp_loc in
       begin match e.pexp_desc with
         | Pexp_apply({pexp_desc=Pexp_ident {txt = Lident "|."; _}; _}, ["", obj_arg; "", fn]) ->
-        (* | Pexp_ident {txt = Lident "|."} -> *)
-          (*
-            a |. f
-            a |. f b c [@bs]  --> f a b c [@bs]
-          *)
-              let new_obj_arg = self.expr self obj_arg in
-              begin match fn with
-                | {pexp_desc = Pexp_apply (fn, args); pexp_loc; _} ->
-                  let fn = self.expr self fn in
-                  let args = List.map (fun (lab,exp) -> lab, self.expr self exp ) args in
-                  { Parsetree.pexp_desc = Pexp_apply(fn, ("", new_obj_arg) :: args);
-                    pexp_attributes = [];
-                    pexp_loc = pexp_loc}
-                | _ -> Exp.apply ~loc (self.expr self fn) ["", new_obj_arg]
-              end
+          let new_obj_arg = self.expr self obj_arg in
+          begin match fn with
+            | {pexp_desc = Pexp_apply (fn, args); pexp_loc; _} ->
+              let fn = self.expr self fn in
+              let args = List.map (fun (lab,exp) -> lab, self.expr self exp ) args in
+              { Parsetree.pexp_desc = Pexp_apply(fn, ("", new_obj_arg) :: args);
+                pexp_attributes = [];
+                pexp_loc = pexp_loc}
+            | {pexp_desc = Pexp_construct (lident, None); pexp_loc; _} ->
+              { Parsetree.pexp_desc = Pexp_construct(lident, (Some new_obj_arg));
+                pexp_attributes = [];
+                pexp_loc = pexp_loc}
+            | _ -> Exp.apply ~loc (self.expr self fn) ["", new_obj_arg]
+          end
         | _ -> Ast_mapper.default_mapper.expr self e
       end
   }
 
-let () = Driver.register ~name:"ppx_lwt" ~args:[] Versions.ocaml_402 (fun _config _cookies -> mapper)
+let () = Driver.register ~name:"ppx_belt" ~args:[] Versions.ocaml_402 (fun _config _cookies -> mapper)

ppx/Ppx_Monads.re

@@ -47,6 +47,9 @@ the result of the whole thing to be unit, use `let%consume`.
 
  */
 
+open Migrate_parsetree
+open OCaml_402.Ast
+
 /***
  * https://ocsigen.org/lwt/dev/api/Ppx_lwt
  * https://github.com/zepalmer/ocaml-monadic
@@ -148,7 +151,7 @@ This is intented for performing side-effects only -- `otherStuff`
 must end up as type `unit`.
 |};
 
-let mapper = _argv =>
+let mapper = 
   Parsetree.{
     ...Ast_mapper.default_mapper,
     expr: (mapper, expr) =>
@@ -184,4 +187,4 @@ let mapper = _argv =>
       }
   };
 
-let () = Ast_mapper.run_main(mapper);
+let () = Driver.register(~name="ppx_monads", ~args=[], Versions.ocaml_402, (_config, _cookies) => mapper);

ppx/dune

@@ -0,0 +1,7 @@
+
+(library
+  (name Ppx_monads)
+  (libraries compiler-libs ocaml-migrate-parsetree ppx_tools_versioned)
+  (preprocess (pps ppx_tools_versioned.metaquot_402))
+  (kind ppx_rewriter))
+

src/analyze/Hover.re

@@ -132,7 +132,7 @@ let newHover = (~rootUri, ~file: SharedTypes.file, ~extra, ~getModule, ~markdown
           }
         };
 
-        Some(String.concat("\n\n", parts |. Belt_List.keepMap(x => x)))
+        Some(String.concat("\n\n", parts |. Belt.List.keepMap(x => x)))
       } |? typeString)
 
     }

src/dune

@@ -3,6 +3,6 @@
 (executable
   (name Bin)
   (public_name Bin)
-  (libraries compiler-libs Belt Vendor ocaml-migrate-parsetree ppx_tools_versioned)
-  (flags :standard -open Vendor)
-  (preprocess (pps Belt_ppx )))
+  (libraries compiler-libs.common Belt Vendor str)
+  (flags :standard -open Vendor -w -26)
+  (preprocess (pps Belt_ppx Ppx_monads)))