fix code generation of objects that refer to a variable in scope (#1183)

* fix code generation of objects that refer to a variable in scope

* update submodule

* chore: add changelog entry

Changes.md

@@ -13,6 +13,8 @@ Unreleased
   ([#1164](https://github.com/melange-re/melange/pull/1164))
 - Fix code generation of custom `true` / `false` constructors
   ([#1175](https://github.com/melange-re/melange/pull/1175))
+- Fix code generation of OCaml objects that refers to an init variable in scope
+  ([#1183](https://github.com/melange-re/melange/pull/1183))
 
 4.0.1 2024-06-07
 ---------------

test/blackbox-tests/objects-close-over-variable.t

@@ -0,0 +1,104 @@
+Test classes that close over an init variable from the outside scope
+
+  $ . ./setup.sh
+  $ cat > dune-project <<EOF
+  > (lang dune 3.9)
+  > (using melange 0.1)
+  > EOF
+
+  $ cat > dune <<EOF
+  > (melange.emit
+  >  (target out)
+  >  (preprocess
+  >   (pps melange.ppx)))
+  > EOF
+
+  $ cat > x.ml <<EOF
+  > let fresh () =
+  >   let r = 2 in
+  >   let dummy = object
+  >     val mutable x = r
+  >     method get_x = x
+  >     method set_x y = x <- y
+  >   end in
+  >   dummy
+  > let () =
+  >   let f = (fresh()) in
+  >   let x = f#get_x in
+  >   Js.log2 "x expect 2" x;
+  >   f#set_x 42 ;
+  >   let y = f#get_x in
+  >   Js.log2 "x expect 42" y;
+  > EOF
+
+  $ dune build @melange
+
+  $ node _build/default/out/x.js
+  x expect 2 2
+  x expect 42 42
+
+  $ cat _build/default/out/x.js
+  // Generated by Melange
+  'use strict';
+  
+  const Caml_oo_curry = require("melange.js/caml_oo_curry.js");
+  const CamlinternalOO = require("melange/camlinternalOO.js");
+  const Curry = require("melange.js/curry.js");
+  
+  const shared = [
+    "set_x",
+    "get_x"
+  ];
+  
+  const object_tables = {
+    TAG: /* Cons */0,
+    key: undefined,
+    data: undefined,
+    next: undefined
+  };
+  
+  function fresh(param) {
+    if (!object_tables.key) {
+      const $$class = CamlinternalOO.create_table(shared);
+      const ids = CamlinternalOO.new_methods_variables($$class, shared, ["x"]);
+      const set_x = ids[0];
+      const get_x = ids[1];
+      const x = ids[2];
+      CamlinternalOO.set_methods($$class, [
+            get_x,
+            (function (self$1) {
+                return self$1[x];
+              }),
+            set_x,
+            (function (self$1, y) {
+                self$1[x] = y;
+              })
+          ]);
+      const env_init = function (env) {
+        const self = CamlinternalOO.create_object_opt(undefined, $$class);
+        self[x] = env[1];
+        return self;
+      };
+      CamlinternalOO.init_class($$class);
+      object_tables.key = env_init;
+    }
+    return Curry._1(object_tables.key, [
+                undefined,
+                2
+              ]);
+  }
+  
+  const f = fresh(undefined);
+  
+  const x = Caml_oo_curry.js1(291546447, 1, f);
+  
+  console.log("x expect 2", x);
+  
+  Caml_oo_curry.js2(-97543333, 2, f, 42);
+  
+  const y = Caml_oo_curry.js1(291546447, 3, f);
+  
+  console.log("x expect 42", y);
+  
+  exports.fresh = fresh;
+  /* f Not a pure module */