From 0732f2e06993eae672d9ef9cf3b942ffdd5c4b5f Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 2 Mar 2024 14:20:52 +1100
Subject: [PATCH 01/12] add public_name stanza

---
 bindgen/dune | 1 +
 1 file changed, 1 insertion(+)

diff --git a/bindgen/dune b/bindgen/dune
index 980ff1b..cc0caf2 100644
--- a/bindgen/dune
+++ b/bindgen/dune
@@ -1,4 +1,5 @@
 (library
+ (public_name bindgen)
  (name bindgen)
  (preprocess
   (pps ppxlib.metaquot))

From d832014d2d1310684379d7413e76dc5caceaa7cc Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 2 Mar 2024 15:02:23 +1100
Subject: [PATCH 02/12] add dog weight as float to example

---
 examples/doggo.c |  4 ++--
 examples/doggo.h |  1 +
 examples/main.ml | 10 ++++++++--
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/examples/doggo.c b/examples/doggo.c
index 60a4784..6df51ff 100644
--- a/examples/doggo.c
+++ b/examples/doggo.c
@@ -11,5 +11,5 @@ static const char* BreedToString[4] = {
 void eleven_out_of_ten_majestic_af(Doggo* pupper) {
   printf("doggo says %d\n", pupper->many);
   printf("doggo is a %s\n", BreedToString[pupper->breed]);
-}
-
+  printf("doggo weighs %.1fkg\n", pupper->weight);
+}
\ No newline at end of file
diff --git a/examples/doggo.h b/examples/doggo.h
index ea8d8dd..6a04634 100644
--- a/examples/doggo.h
+++ b/examples/doggo.h
@@ -9,6 +9,7 @@ typedef struct Doggo {
     int many;
     breed breed;
     char wow;
+    float weight;
 } Doggo;
 
 void eleven_out_of_ten_majestic_af(Doggo* pupper);
diff --git a/examples/main.ml b/examples/main.ml
index 120443f..0398f08 100644
--- a/examples/main.ml
+++ b/examples/main.ml
@@ -1,5 +1,11 @@
-Doggo.eleven_out_of_ten_majestic_af ~pupper:{
+open Doggo
+
+let pupper = {
   many=2112;
   wow='x';
-  breed=C_Labrador
+  breed=C_Labrador;
+  weight=18.9;
 }
+
+let () =
+  Doggo.eleven_out_of_ten_majestic_af ~pupper
\ No newline at end of file

From 292906ac1aa0f1129d665f06b2bf375fb131a0a2 Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 2 Mar 2024 15:03:00 +1100
Subject: [PATCH 03/12] float primitive first pass

---
 bindgen/c.ml    | 63 ++++++++++++++++++++++++++++++-------------------
 bindgen/caml.ml |  1 +
 bindgen/ir.ml   |  3 ++-
 3 files changed, 42 insertions(+), 25 deletions(-)

diff --git a/bindgen/c.ml b/bindgen/c.ml
index 20b4b41..cbee800 100644
--- a/bindgen/c.ml
+++ b/bindgen/c.ml
@@ -1,7 +1,7 @@
 let caml_ = "caml_"
 
 type c_type = Prim of string | Struct of string | Ptr of c_type | Void
-type c_prim = Int of int | Str of string
+type c_prim = Int of int | Float of float | Str of string
 
 type t =
   | C_function of {
@@ -23,7 +23,6 @@ type t =
 
 type program = t list
 
-
 let pp_list sep pp_el fmt t =
   Format.pp_print_list
     ~pp_sep:(fun fmt () -> Format.fprintf fmt "%s" sep)
@@ -66,6 +65,7 @@ and pp_type fmt (ctype : c_type) =
 and pp_prim fmt (prim : c_prim) =
   match prim with
   | Int d -> Format.fprintf fmt "%d" d
+  | Float f -> Format.fprintf fmt "%f" f
   | Str s -> Format.fprintf fmt "%s" s
 
 let decl dcl_type dcl_name dcl_value = C_decl { dcl_name; dcl_type; dcl_value }
@@ -73,6 +73,7 @@ let call cc_name cc_args = C_call { cc_name; cc_args }
 let var x = C_variable x
 let assign asg_var asg_value = C_assign { asg_var; asg_value }
 let int x = C_prim (Int x)
+let float f = C_prim (Float f)
 let string x = C_prim (Str x)
 let ptr_field pfa_name pfa_field = C_ptr_field_access { pfa_name; pfa_field }
 let typ t = C_type t
@@ -90,7 +91,11 @@ let caml_alloc_tuple fields =
 
 let store_field var idx value = call "Store_field" [ var; int idx; value ]
 let val_int var name = call "Val_int" [ ptr_field var name ]
-let int_val var idx = call "Int_val" [ call "Field" [ var; int idx] ]
+let int_val var idx = call "Int_val" [ call "Field" [ var; int idx ] ]
+
+(* Unlike Int, Float must be re-boxed before returning to the OCaml runtime thus a copy*)
+let val_float var name = call "caml_copy_double" [ ptr_field var name ]
+let float_val var idx = call "Double_val" [ call "Field" [ var; int idx ] ]
 
 (* from_ir *)
 let rec ctype_of_ir (ir_type : Ir.ir_type) =
@@ -99,6 +104,7 @@ let rec ctype_of_ir (ir_type : Ir.ir_type) =
   | Ir.Record { rec_name; _ } -> Prim rec_name
   | Ir.Enum { enum_name; _ } -> Prim enum_name
   | Ir.Prim Ir.Int -> Prim "int"
+  | Ir.Prim Ir.Float -> Prim "float"
   | Ir.Prim Ir.Bool -> Prim "bool"
   | Ir.Prim Ir.Char -> Prim "char"
   | Ir.Prim Ir.Void -> Void
@@ -127,9 +133,13 @@ module Shims = struct
           ]
           @ Ir.(
               List.mapi
-                (fun idx field ->
-                  store_field (var "caml_x") idx
-                    (val_int (var "x") field.fld_name))
+                (fun idx fld ->
+                  let fld_caml_value =
+                    match fld.fld_type with
+                    | Prim Float -> val_float (var "x") fld.fld_name
+                    | _ -> val_int (var "x") fld.fld_name
+                  in
+                  store_field (var "caml_x") idx fld_caml_value)
                 fields)
           @ [ caml_return (var "caml_x") ];
       }
@@ -148,9 +158,12 @@ module Shims = struct
           @ Ir.(
               List.mapi
                 (fun idx fld ->
-                  assign
-                    (ptr_field (var "x") fld.fld_name)
-                    (int_val (var "caml_x") idx))
+                  let field_c_value =
+                    match fld.fld_type with
+                    | Prim Float -> float_val (var "caml_x") idx
+                    | _ -> int_val (var "caml_x") idx
+                  in
+                  assign (ptr_field (var "x") fld.fld_name) field_c_value)
                 fields)
           @ [ return (var "x") ];
       }
@@ -162,7 +175,10 @@ module Shims = struct
 
         let fn_body =
           let declare_params =
-            [ caml_params (List.map (fun (name, _type) -> var (caml_^name)) fn_params ) ]
+            [
+              caml_params
+                (List.map (fun (name, _type) -> var (caml_ ^ name)) fn_params);
+            ]
           in
           let maybe_declare_result =
             match fn_ret with
@@ -224,17 +240,16 @@ let from_ir (ir : Ir.t) : program =
     C_include "<caml/mlvalues.h>";
     C_include "<caml/unixsupport.h>";
   ]
-  @
-  (List.filter_map
-    (fun node ->
-      match node with
-      | Ir.Ir_fun_decl fun_decl -> Some [ Shims.wrap_fun fun_decl ]
-      | Ir.Ir_type (Record { rec_name; rec_fields }) ->
-          Some
-            [
-              Shims.of_value rec_name rec_fields;
-              Shims.to_value rec_name rec_fields;
-            ]
-      | _ -> None)
-    ir.items
-  |> List.flatten)
+  @ (List.filter_map
+       (fun node ->
+         match node with
+         | Ir.Ir_fun_decl fun_decl -> Some [ Shims.wrap_fun fun_decl ]
+         | Ir.Ir_type (Record { rec_name; rec_fields }) ->
+             Some
+               [
+                 Shims.of_value rec_name rec_fields;
+                 Shims.to_value rec_name rec_fields;
+               ]
+         | _ -> None)
+       ir.items
+    |> List.flatten)
diff --git a/bindgen/caml.ml b/bindgen/caml.ml
index 6f8ca97..eb7942b 100644
--- a/bindgen/caml.ml
+++ b/bindgen/caml.ml
@@ -28,6 +28,7 @@ let rec core_type_from_ir typ =
   | Ir.Enum { enum_name; _ } -> Typ.constr (lid enum_name) []
   | Ir.Record { rec_name; _ } -> Typ.constr (lid rec_name) []
   | Ir.Prim Int -> Typ.constr (lid "int") []
+  | Ir.Prim Float -> Typ.constr (lid "float") []
   | Ir.Prim Bool -> Typ.constr (lid "bool") []
   | Ir.Prim Char -> Typ.constr (lid "char") []
   | Ir.Prim Void -> Typ.constr (lid "unit") []
diff --git a/bindgen/ir.ml b/bindgen/ir.ml
index 13b4b8e..b0d021c 100644
--- a/bindgen/ir.ml
+++ b/bindgen/ir.ml
@@ -1,4 +1,4 @@
-type ir_prim_type = Int | Bool | Char | Void
+type ir_prim_type = Int | Float | Bool | Char | Void
 
 type ir_type =
   | Abstract of string
@@ -23,6 +23,7 @@ module Lift = struct
     (* Format.printf "lift_type: %S\n" (Clang.Type.show typ); *)
     match typ.desc with
     | Clang.Ast.BuiltinType Int -> Prim Int
+    | Clang.Ast.BuiltinType Float -> Prim Float
     | Clang.Ast.BuiltinType Bool -> Prim Bool
     | Clang.Ast.BuiltinType Char_S -> Prim Char
     | Clang.Ast.BuiltinType Void -> Prim Void

From 66affc7af2ca97eb413447091a63685dfce0b3c1 Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 2 Mar 2024 15:03:12 +1100
Subject: [PATCH 04/12] generated output for floating point

---
 examples/caml_doggo.c | 4 +++-
 examples/doggo.ml     | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/examples/caml_doggo.c b/examples/caml_doggo.c
index 73f3e38..468cba1 100644
--- a/examples/caml_doggo.c
+++ b/examples/caml_doggo.c
@@ -11,16 +11,18 @@ Doggo* caml_Doggo_of_value(value caml_x) {
   x->many = Int_val(Field(caml_x, 0));
   x->breed = Int_val(Field(caml_x, 1));
   x->wow = Int_val(Field(caml_x, 2));
+  x->weight = Double_val(Field(caml_x, 3));
   return x;
 }
 
 value caml_Doggo_to_value(struct Doggo* x) {
   CAMLparam0();
   CAMLlocal1(caml_x);
-  caml_x = caml_alloc_tuple(3);
+  caml_x = caml_alloc_tuple(4);
   Store_field(caml_x, 0, Val_int(x->many));
   Store_field(caml_x, 1, Val_int(x->breed));
   Store_field(caml_x, 2, Val_int(x->wow));
+  Store_field(caml_x, 3, caml_copy_double(x->weight));
   CAMLreturn(caml_x);
 }
 
diff --git a/examples/doggo.ml b/examples/doggo.ml
index 9b9bbe2..3d21fa7 100644
--- a/examples/doggo.ml
+++ b/examples/doggo.ml
@@ -7,6 +7,7 @@ type nonrec breed =
 type nonrec doggo = {
   many: int ;
   breed: breed ;
-  wow: char }
+  wow: char ;
+  weight: float }
 external eleven_out_of_ten_majestic_af :
   pupper:doggo -> unit = "caml_eleven_out_of_ten_majestic_af"

From 725e1306ec407c0cf03c7c06889bf98d71489402 Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 2 Mar 2024 15:02:23 +1100
Subject: [PATCH 05/12] add dog weight as float to example

---
 examples/doggo.c |  4 ++--
 examples/doggo.h |  1 +
 examples/main.ml | 10 ++++++++--
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/examples/doggo.c b/examples/doggo.c
index 60a4784..6df51ff 100644
--- a/examples/doggo.c
+++ b/examples/doggo.c
@@ -11,5 +11,5 @@ static const char* BreedToString[4] = {
 void eleven_out_of_ten_majestic_af(Doggo* pupper) {
   printf("doggo says %d\n", pupper->many);
   printf("doggo is a %s\n", BreedToString[pupper->breed]);
-}
-
+  printf("doggo weighs %.1fkg\n", pupper->weight);
+}
\ No newline at end of file
diff --git a/examples/doggo.h b/examples/doggo.h
index ea8d8dd..6a04634 100644
--- a/examples/doggo.h
+++ b/examples/doggo.h
@@ -9,6 +9,7 @@ typedef struct Doggo {
     int many;
     breed breed;
     char wow;
+    float weight;
 } Doggo;
 
 void eleven_out_of_ten_majestic_af(Doggo* pupper);
diff --git a/examples/main.ml b/examples/main.ml
index 120443f..0398f08 100644
--- a/examples/main.ml
+++ b/examples/main.ml
@@ -1,5 +1,11 @@
-Doggo.eleven_out_of_ten_majestic_af ~pupper:{
+open Doggo
+
+let pupper = {
   many=2112;
   wow='x';
-  breed=C_Labrador
+  breed=C_Labrador;
+  weight=18.9;
 }
+
+let () =
+  Doggo.eleven_out_of_ten_majestic_af ~pupper
\ No newline at end of file

From 89bc86401afe95cb3659c053069bcb5e859fee68 Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 2 Mar 2024 15:03:00 +1100
Subject: [PATCH 06/12] float primitive first pass

---
 bindgen/c.ml    | 63 ++++++++++++++++++++++++++++++-------------------
 bindgen/caml.ml |  1 +
 bindgen/ir.ml   |  3 ++-
 3 files changed, 42 insertions(+), 25 deletions(-)

diff --git a/bindgen/c.ml b/bindgen/c.ml
index 20b4b41..cbee800 100644
--- a/bindgen/c.ml
+++ b/bindgen/c.ml
@@ -1,7 +1,7 @@
 let caml_ = "caml_"
 
 type c_type = Prim of string | Struct of string | Ptr of c_type | Void
-type c_prim = Int of int | Str of string
+type c_prim = Int of int | Float of float | Str of string
 
 type t =
   | C_function of {
@@ -23,7 +23,6 @@ type t =
 
 type program = t list
 
-
 let pp_list sep pp_el fmt t =
   Format.pp_print_list
     ~pp_sep:(fun fmt () -> Format.fprintf fmt "%s" sep)
@@ -66,6 +65,7 @@ and pp_type fmt (ctype : c_type) =
 and pp_prim fmt (prim : c_prim) =
   match prim with
   | Int d -> Format.fprintf fmt "%d" d
+  | Float f -> Format.fprintf fmt "%f" f
   | Str s -> Format.fprintf fmt "%s" s
 
 let decl dcl_type dcl_name dcl_value = C_decl { dcl_name; dcl_type; dcl_value }
@@ -73,6 +73,7 @@ let call cc_name cc_args = C_call { cc_name; cc_args }
 let var x = C_variable x
 let assign asg_var asg_value = C_assign { asg_var; asg_value }
 let int x = C_prim (Int x)
+let float f = C_prim (Float f)
 let string x = C_prim (Str x)
 let ptr_field pfa_name pfa_field = C_ptr_field_access { pfa_name; pfa_field }
 let typ t = C_type t
@@ -90,7 +91,11 @@ let caml_alloc_tuple fields =
 
 let store_field var idx value = call "Store_field" [ var; int idx; value ]
 let val_int var name = call "Val_int" [ ptr_field var name ]
-let int_val var idx = call "Int_val" [ call "Field" [ var; int idx] ]
+let int_val var idx = call "Int_val" [ call "Field" [ var; int idx ] ]
+
+(* Unlike Int, Float must be re-boxed before returning to the OCaml runtime thus a copy*)
+let val_float var name = call "caml_copy_double" [ ptr_field var name ]
+let float_val var idx = call "Double_val" [ call "Field" [ var; int idx ] ]
 
 (* from_ir *)
 let rec ctype_of_ir (ir_type : Ir.ir_type) =
@@ -99,6 +104,7 @@ let rec ctype_of_ir (ir_type : Ir.ir_type) =
   | Ir.Record { rec_name; _ } -> Prim rec_name
   | Ir.Enum { enum_name; _ } -> Prim enum_name
   | Ir.Prim Ir.Int -> Prim "int"
+  | Ir.Prim Ir.Float -> Prim "float"
   | Ir.Prim Ir.Bool -> Prim "bool"
   | Ir.Prim Ir.Char -> Prim "char"
   | Ir.Prim Ir.Void -> Void
@@ -127,9 +133,13 @@ module Shims = struct
           ]
           @ Ir.(
               List.mapi
-                (fun idx field ->
-                  store_field (var "caml_x") idx
-                    (val_int (var "x") field.fld_name))
+                (fun idx fld ->
+                  let fld_caml_value =
+                    match fld.fld_type with
+                    | Prim Float -> val_float (var "x") fld.fld_name
+                    | _ -> val_int (var "x") fld.fld_name
+                  in
+                  store_field (var "caml_x") idx fld_caml_value)
                 fields)
           @ [ caml_return (var "caml_x") ];
       }
@@ -148,9 +158,12 @@ module Shims = struct
           @ Ir.(
               List.mapi
                 (fun idx fld ->
-                  assign
-                    (ptr_field (var "x") fld.fld_name)
-                    (int_val (var "caml_x") idx))
+                  let field_c_value =
+                    match fld.fld_type with
+                    | Prim Float -> float_val (var "caml_x") idx
+                    | _ -> int_val (var "caml_x") idx
+                  in
+                  assign (ptr_field (var "x") fld.fld_name) field_c_value)
                 fields)
           @ [ return (var "x") ];
       }
@@ -162,7 +175,10 @@ module Shims = struct
 
         let fn_body =
           let declare_params =
-            [ caml_params (List.map (fun (name, _type) -> var (caml_^name)) fn_params ) ]
+            [
+              caml_params
+                (List.map (fun (name, _type) -> var (caml_ ^ name)) fn_params);
+            ]
           in
           let maybe_declare_result =
             match fn_ret with
@@ -224,17 +240,16 @@ let from_ir (ir : Ir.t) : program =
     C_include "<caml/mlvalues.h>";
     C_include "<caml/unixsupport.h>";
   ]
-  @
-  (List.filter_map
-    (fun node ->
-      match node with
-      | Ir.Ir_fun_decl fun_decl -> Some [ Shims.wrap_fun fun_decl ]
-      | Ir.Ir_type (Record { rec_name; rec_fields }) ->
-          Some
-            [
-              Shims.of_value rec_name rec_fields;
-              Shims.to_value rec_name rec_fields;
-            ]
-      | _ -> None)
-    ir.items
-  |> List.flatten)
+  @ (List.filter_map
+       (fun node ->
+         match node with
+         | Ir.Ir_fun_decl fun_decl -> Some [ Shims.wrap_fun fun_decl ]
+         | Ir.Ir_type (Record { rec_name; rec_fields }) ->
+             Some
+               [
+                 Shims.of_value rec_name rec_fields;
+                 Shims.to_value rec_name rec_fields;
+               ]
+         | _ -> None)
+       ir.items
+    |> List.flatten)
diff --git a/bindgen/caml.ml b/bindgen/caml.ml
index 6f8ca97..eb7942b 100644
--- a/bindgen/caml.ml
+++ b/bindgen/caml.ml
@@ -28,6 +28,7 @@ let rec core_type_from_ir typ =
   | Ir.Enum { enum_name; _ } -> Typ.constr (lid enum_name) []
   | Ir.Record { rec_name; _ } -> Typ.constr (lid rec_name) []
   | Ir.Prim Int -> Typ.constr (lid "int") []
+  | Ir.Prim Float -> Typ.constr (lid "float") []
   | Ir.Prim Bool -> Typ.constr (lid "bool") []
   | Ir.Prim Char -> Typ.constr (lid "char") []
   | Ir.Prim Void -> Typ.constr (lid "unit") []
diff --git a/bindgen/ir.ml b/bindgen/ir.ml
index 13b4b8e..b0d021c 100644
--- a/bindgen/ir.ml
+++ b/bindgen/ir.ml
@@ -1,4 +1,4 @@
-type ir_prim_type = Int | Bool | Char | Void
+type ir_prim_type = Int | Float | Bool | Char | Void
 
 type ir_type =
   | Abstract of string
@@ -23,6 +23,7 @@ module Lift = struct
     (* Format.printf "lift_type: %S\n" (Clang.Type.show typ); *)
     match typ.desc with
     | Clang.Ast.BuiltinType Int -> Prim Int
+    | Clang.Ast.BuiltinType Float -> Prim Float
     | Clang.Ast.BuiltinType Bool -> Prim Bool
     | Clang.Ast.BuiltinType Char_S -> Prim Char
     | Clang.Ast.BuiltinType Void -> Prim Void

From 44d7a3a7d5f4c4c8a8633dac498da1ece2a5c081 Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 2 Mar 2024 15:03:12 +1100
Subject: [PATCH 07/12] generated output for floating point

---
 examples/caml_doggo.c | 4 +++-
 examples/doggo.ml     | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/examples/caml_doggo.c b/examples/caml_doggo.c
index 73f3e38..468cba1 100644
--- a/examples/caml_doggo.c
+++ b/examples/caml_doggo.c
@@ -11,16 +11,18 @@ Doggo* caml_Doggo_of_value(value caml_x) {
   x->many = Int_val(Field(caml_x, 0));
   x->breed = Int_val(Field(caml_x, 1));
   x->wow = Int_val(Field(caml_x, 2));
+  x->weight = Double_val(Field(caml_x, 3));
   return x;
 }
 
 value caml_Doggo_to_value(struct Doggo* x) {
   CAMLparam0();
   CAMLlocal1(caml_x);
-  caml_x = caml_alloc_tuple(3);
+  caml_x = caml_alloc_tuple(4);
   Store_field(caml_x, 0, Val_int(x->many));
   Store_field(caml_x, 1, Val_int(x->breed));
   Store_field(caml_x, 2, Val_int(x->wow));
+  Store_field(caml_x, 3, caml_copy_double(x->weight));
   CAMLreturn(caml_x);
 }
 
diff --git a/examples/doggo.ml b/examples/doggo.ml
index 9b9bbe2..3d21fa7 100644
--- a/examples/doggo.ml
+++ b/examples/doggo.ml
@@ -7,6 +7,7 @@ type nonrec breed =
 type nonrec doggo = {
   many: int ;
   breed: breed ;
-  wow: char }
+  wow: char ;
+  weight: float }
 external eleven_out_of_ten_majestic_af :
   pupper:doggo -> unit = "caml_eleven_out_of_ten_majestic_af"

From 223ab376543b625d57446f39ad9a0cf5914f03a4 Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 2 Mar 2024 17:48:50 +1100
Subject: [PATCH 08/12] handle libclang double as well

---
 bindgen/ir.ml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/bindgen/ir.ml b/bindgen/ir.ml
index b0d021c..e2b06d9 100644
--- a/bindgen/ir.ml
+++ b/bindgen/ir.ml
@@ -24,6 +24,7 @@ module Lift = struct
     match typ.desc with
     | Clang.Ast.BuiltinType Int -> Prim Int
     | Clang.Ast.BuiltinType Float -> Prim Float
+    | Clang.Ast.BuiltinType Double -> Prim Float
     | Clang.Ast.BuiltinType Bool -> Prim Bool
     | Clang.Ast.BuiltinType Char_S -> Prim Char
     | Clang.Ast.BuiltinType Void -> Prim Void

From 84028353fc60675412173980ebd6bfabffd2b97c Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 2 Mar 2024 17:55:03 +1100
Subject: [PATCH 09/12] remove comment

---
 bindgen/c.ml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/bindgen/c.ml b/bindgen/c.ml
index cbee800..b7c5bad 100644
--- a/bindgen/c.ml
+++ b/bindgen/c.ml
@@ -93,7 +93,6 @@ let store_field var idx value = call "Store_field" [ var; int idx; value ]
 let val_int var name = call "Val_int" [ ptr_field var name ]
 let int_val var idx = call "Int_val" [ call "Field" [ var; int idx ] ]
 
-(* Unlike Int, Float must be re-boxed before returning to the OCaml runtime thus a copy*)
 let val_float var name = call "caml_copy_double" [ ptr_field var name ]
 let float_val var idx = call "Double_val" [ call "Field" [ var; int idx ] ]
 

From 3ae761389878ea4c281a50500e1f2a2a884d9e66 Mon Sep 17 00:00:00 2001
From: omnisci3nce <17525998+omnisci3nce@users.noreply.github.com>
Date: Sat, 9 Mar 2024 18:15:21 +1100
Subject: [PATCH 10/12] Empty function parameters become unit param

Directly match out an empty list rather than using empty string "" for
label.
---
 bindgen/caml.ml       | 21 ++++++++++++++-------
 examples/caml_doggo.c |  6 ++++++
 examples/doggo.c      |  3 +++
 examples/doggo.h      |  2 ++
 examples/doggo.ml     |  1 +
 5 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/bindgen/caml.ml b/bindgen/caml.ml
index 6f8ca97..50353aa 100644
--- a/bindgen/caml.ml
+++ b/bindgen/caml.ml
@@ -32,13 +32,20 @@ let rec core_type_from_ir typ =
   | Ir.Prim Char -> Typ.constr (lid "char") []
   | Ir.Prim Void -> Typ.constr (lid "unit") []
   | Ir.Ptr t -> core_type_from_ir t
-  | Ir.Func { fn_ret; fn_params } ->
-      List.fold_left
-        (fun acc (name, typ) ->
-          let label = Asttypes.Labelled name in
-          let typ = core_type_from_ir typ in
-          Typ.arrow label typ acc)
-        (core_type_from_ir fn_ret) fn_params
+  | Ir.Func { fn_ret; fn_params } -> (
+      match fn_params with
+      | [] ->
+          (* If the C function declaration has no parameters we must introduce a `unit` param *)
+          Typ.arrow Asttypes.Nolabel
+            (core_type_from_ir (Ir.Prim Void))
+            (core_type_from_ir fn_ret)
+      | params ->
+          List.fold_left
+            (fun acc (name, typ) ->
+              let label = Asttypes.Labelled name in
+              let typ = core_type_from_ir typ in
+              Typ.arrow label typ acc)
+            (core_type_from_ir fn_ret) params)
 
 let type_from_ir typ =
   match typ with
diff --git a/examples/caml_doggo.c b/examples/caml_doggo.c
index 73f3e38..35536cb 100644
--- a/examples/caml_doggo.c
+++ b/examples/caml_doggo.c
@@ -31,4 +31,10 @@ void caml_eleven_out_of_ten_majestic_af(value caml_pupper) {
   CAMLreturn0;
 }
 
+void caml_no_input_no_output() {
+  CAMLparam0();
+  no_input_no_output();
+  CAMLreturn0;
+}
+
 
diff --git a/examples/doggo.c b/examples/doggo.c
index 60a4784..bbf5c9d 100644
--- a/examples/doggo.c
+++ b/examples/doggo.c
@@ -13,3 +13,6 @@ void eleven_out_of_ten_majestic_af(Doggo* pupper) {
   printf("doggo is a %s\n", BreedToString[pupper->breed]);
 }
 
+void no_input_no_output(void) {
+  printf("We are doing nothing (of importance)\n");
+}
\ No newline at end of file
diff --git a/examples/doggo.h b/examples/doggo.h
index ea8d8dd..cc65fe9 100644
--- a/examples/doggo.h
+++ b/examples/doggo.h
@@ -12,3 +12,5 @@ typedef struct Doggo {
 } Doggo;
 
 void eleven_out_of_ten_majestic_af(Doggo* pupper);
+
+void no_input_no_output(void);
\ No newline at end of file
diff --git a/examples/doggo.ml b/examples/doggo.ml
index 9b9bbe2..ca1434a 100644
--- a/examples/doggo.ml
+++ b/examples/doggo.ml
@@ -10,3 +10,4 @@ type nonrec doggo = {
   wow: char }
 external eleven_out_of_ten_majestic_af :
   pupper:doggo -> unit = "caml_eleven_out_of_ten_majestic_af"
+external no_input_no_output : unit -> unit = "caml_no_input_no_output"

From 82d651cc63daa5ddb8b982bb145740f2f00734db Mon Sep 17 00:00:00 2001
From: omnisci3nce <17525998+omnisci3nce@users.noreply.github.com>
Date: Sun, 10 Mar 2024 23:21:15 +1100
Subject: [PATCH 11/12] brainstorming how to do pointer arguments

---
 bindgen/caml.ml         |  2 +-
 bindgen/codegen.ml      |  6 ++++++
 bindgen/experimental.ml | 19 +++++++++++++++++++
 bindgen/ir.ml           |  2 +-
 examples/caml_doggo.c   | 34 ++++------------------------------
 examples/doggo.c        | 34 +++++++++++++++++++++-------------
 examples/doggo.h        | 31 +++++++++++++++++--------------
 examples/doggo.ml       | 31 ++++++++++++++++++-------------
 examples/dune           |  1 +
 examples/main.ml        |  9 +++++++--
 10 files changed, 95 insertions(+), 74 deletions(-)
 create mode 100644 bindgen/experimental.ml

diff --git a/bindgen/caml.ml b/bindgen/caml.ml
index cc4be8b..9de625a 100644
--- a/bindgen/caml.ml
+++ b/bindgen/caml.ml
@@ -32,7 +32,7 @@ let rec core_type_from_ir typ =
   | Ir.Prim Bool -> Typ.constr (lid "bool") []
   | Ir.Prim Char -> Typ.constr (lid "char") []
   | Ir.Prim Void -> Typ.constr (lid "unit") []
-  | Ir.Ptr t -> core_type_from_ir t
+  | Ir.Ptr t -> Typ.constr (lid "ptr") [(core_type_from_ir t)]
   | Ir.Func { fn_ret; fn_params } -> (
       match fn_params with
       | [] ->
diff --git a/bindgen/codegen.ml b/bindgen/codegen.ml
index c4935d1..a974ef5 100644
--- a/bindgen/codegen.ml
+++ b/bindgen/codegen.ml
@@ -5,6 +5,9 @@ let with_file file fn =
   close_out oc;
   ()
 
+let read_file file =
+  In_channel.with_open_bin file In_channel.input_all
+
 let write_dune_file (dune : Dunefile.t) =
   with_file "dune" @@ fun fmt ->
   Format.fprintf fmt
@@ -22,8 +25,11 @@ let write_dune_file (dune : Dunefile.t) =
   Format.fprintf fmt "\n%!"
 
 let write_caml_files caml (dune : Dunefile.t) =
+  let experimental = read_file "../bindgen/experimental.ml" in
   with_file dune.caml_file_name @@ fun fmt ->
   Format.fprintf fmt "(* automatically generated by ocaml-bindgen 0.0.1 *)\n";
+  (* Format.fprintf fmt "open Bindgen.Experimental\n"; *)
+  Format.fprintf fmt "%s\n" experimental;
   Format.fprintf fmt "%s\n%!" (Format.asprintf "%a" Pprintast.structure caml)
 
 let write_c_files (c : C.program) (dune : Dunefile.t) =
diff --git a/bindgen/experimental.ml b/bindgen/experimental.ml
new file mode 100644
index 0000000..9553fe9
--- /dev/null
+++ b/bindgen/experimental.ml
@@ -0,0 +1,19 @@
+type lifetime =
+  Function (** The value can live for the lifetime of the function call, which upon return will signal that the 
+               value can be dropped (finalizer?) *)
+  | Ocaml  (** The value is managed by the OCaml runtime *)
+  | C      (** The value is allocated and passed to C which is then in charge of cleaning it up *)
+
+type 'a ptr = {
+  lifetime: lifetime;
+  value: 'a;
+}
+
+(* The easiest way to call a function that requires a int ptr is to do *)
+
+(* basically we need a funtion
+  string -> char ptr that we can then pass to the function   
+*)
+
+
+(* let char_ptr (s: string) : char ptr = {} *)
\ No newline at end of file
diff --git a/bindgen/ir.ml b/bindgen/ir.ml
index b0d021c..f484931 100644
--- a/bindgen/ir.ml
+++ b/bindgen/ir.ml
@@ -20,7 +20,7 @@ module Lift = struct
     match name with Clang.Ast.IdentifierName x -> x | _ -> assert false
 
   let rec lift_type (typ : Clang.Type.t) =
-    (* Format.printf "lift_type: %S\n" (Clang.Type.show typ); *)
+    Format.printf "lift_type: %S\n" (Clang.Type.show typ); flush stdout;
     match typ.desc with
     | Clang.Ast.BuiltinType Int -> Prim Int
     | Clang.Ast.BuiltinType Float -> Prim Float
diff --git a/examples/caml_doggo.c b/examples/caml_doggo.c
index 60072d0..90cd74a 100644
--- a/examples/caml_doggo.c
+++ b/examples/caml_doggo.c
@@ -6,36 +6,10 @@
 #include <caml/memory.h>
 #include <caml/mlvalues.h>
 #include <caml/unixsupport.h>
-Doggo* caml_Doggo_of_value(value caml_x) {
-  Doggo* x = malloc(sizeof(struct Doggo));
-  x->many = Int_val(Field(caml_x, 0));
-  x->breed = Int_val(Field(caml_x, 1));
-  x->wow = Int_val(Field(caml_x, 2));
-  x->weight = Double_val(Field(caml_x, 3));
-  return x;
-}
-
-value caml_Doggo_to_value(struct Doggo* x) {
-  CAMLparam0();
-  CAMLlocal1(caml_x);
-  caml_x = caml_alloc_tuple(4);
-  Store_field(caml_x, 0, Val_int(x->many));
-  Store_field(caml_x, 1, Val_int(x->breed));
-  Store_field(caml_x, 2, Val_int(x->wow));
-  Store_field(caml_x, 3, caml_copy_double(x->weight));
-  CAMLreturn(caml_x);
-}
-
-void caml_eleven_out_of_ten_majestic_af(value caml_pupper) {
-  CAMLparam1(caml_pupper);
-  Doggo* pupper = caml_Doggo_of_value(caml_pupper);
-  eleven_out_of_ten_majestic_af(pupper);
-  CAMLreturn0;
-}
-
-void caml_no_input_no_output() {
-  CAMLparam0();
-  no_input_no_output();
+void caml_print_age(value caml_age) {
+  CAMLparam1(caml_age);
+  int* age = caml_int_of_value(caml_age);
+  print_age(age);
   CAMLreturn0;
 }
 
diff --git a/examples/doggo.c b/examples/doggo.c
index 76c33c0..473d63b 100644
--- a/examples/doggo.c
+++ b/examples/doggo.c
@@ -1,19 +1,27 @@
 #include <stdio.h>
 #include "doggo.h"
 
-static const char* BreedToString[4] = {
-  "Labrador",
-  "Golden Retriever",
-  "Pug",
-  "Poodle"
-};
+// static const char* BreedToString[4] = {
+//   "Labrador",
+//   "Golden Retriever",
+//   "Pug",
+//   "Poodle"
+// };
 
-void eleven_out_of_ten_majestic_af(Doggo* pupper) {
-  printf("doggo says %d\n", pupper->many);
-  printf("doggo is a %s\n", BreedToString[pupper->breed]);
-  printf("doggo weighs %.1fkg\n", pupper->weight);
+// void eleven_out_of_ten_majestic_af(Doggo* pupper) {
+//   printf("doggo says %d\n", pupper->many);
+//   printf("doggo is a %s\n", BreedToString[pupper->breed]);
+//   printf("doggo weighs %.1fkg\n", pupper->weight);
+// }
+
+// void no_input_no_output(void) {
+//   printf("We are doing nothing (of importance)\n");
+// }
+
+void print_age(int* age) {
+  printf("Age: %d\n", *age);
 }
 
-void no_input_no_output(void) {
-  printf("We are doing nothing (of importance)\n");
-}
\ No newline at end of file
+// void greet_dog(char* dog_name) {
+//   printf("Hey %s\n", dog_name);
+// }
\ No newline at end of file
diff --git a/examples/doggo.h b/examples/doggo.h
index b19ff07..128c42d 100644
--- a/examples/doggo.h
+++ b/examples/doggo.h
@@ -1,17 +1,20 @@
-typedef enum breed {
-    Labrador,
-    _GoldenRetriever,
-    pug,
-    _poodle
-} breed;
+// typedef enum breed {
+//     Labrador,
+//     _GoldenRetriever,
+//     pug,
+//     _poodle
+// } breed;
 
-typedef struct Doggo {
-    int many;
-    breed breed;
-    char wow;
-    float weight;
-} Doggo;
+// typedef struct Doggo {
+//     int many;
+//     breed breed;
+//     char wow;
+//     float weight;
+// } Doggo;
 
-void eleven_out_of_ten_majestic_af(Doggo* pupper);
+// void eleven_out_of_ten_majestic_af(Doggo* pupper);
 
-void no_input_no_output(void);
\ No newline at end of file
+// void no_input_no_output(void);
+
+void print_age(int* age);
+// void greet_dog(char* dog_name);
\ No newline at end of file
diff --git a/examples/doggo.ml b/examples/doggo.ml
index 8278468..d4ffa20 100644
--- a/examples/doggo.ml
+++ b/examples/doggo.ml
@@ -1,14 +1,19 @@
 (* automatically generated by ocaml-bindgen 0.0.1 *)
-type nonrec breed =
-  | C_Labrador 
-  | C__GoldenRetriever 
-  | C_pug 
-  | C__poodle 
-type nonrec doggo = {
-  many: int ;
-  breed: breed ;
-  wow: char ;
-  weight: float }
-external eleven_out_of_ten_majestic_af :
-  pupper:doggo -> unit = "caml_eleven_out_of_ten_majestic_af"
-external no_input_no_output : unit -> unit = "caml_no_input_no_output"
+type lifetime =
+  Function (** The value can live for the lifetime of the function call, which upon return will signal that the 
+               value can be dropped (finalizer?) *)
+  | Ocaml  (** The value is managed by the OCaml runtime *)
+  | C      (** The value is allocated and passed to C which is then in charge of cleaning it up *)
+
+type 'a ptr = {
+  lifetime: lifetime;
+  value: 'a;
+}
+
+(* basically we need a funtion
+  string -> char ptr that we can then pass to the function   
+*)
+
+
+(* let char_ptr (s: string) : char ptr = {} *)
+external print_age : age:int ptr -> unit = "caml_print_age"
diff --git a/examples/dune b/examples/dune
index e31905b..6f247d7 100644
--- a/examples/dune
+++ b/examples/dune
@@ -1,5 +1,6 @@
 (executable
   (name main)
+  (libraries bindgen)
  (foreign_stubs
   (language c)
   (names doggo caml_doggo)
diff --git a/examples/main.ml b/examples/main.ml
index 0398f08..b1a6565 100644
--- a/examples/main.ml
+++ b/examples/main.ml
@@ -1,6 +1,6 @@
 open Doggo
 
-let pupper = {
+(* let pupper = {
   many=2112;
   wow='x';
   breed=C_Labrador;
@@ -8,4 +8,9 @@ let pupper = {
 }
 
 let () =
-  Doggo.eleven_out_of_ten_majestic_af ~pupper
\ No newline at end of file
+  Doggo.eleven_out_of_ten_majestic_af ~pupper *)
+
+let char_ptr_of_string = 
+
+let () =
+  greet_dog ~dog_name:"Puppy"
\ No newline at end of file

From 701106b08db6c19ad01caa5d27ae877d68d0272c Mon Sep 17 00:00:00 2001
From: Omniscient <omniscient.oce@gmail.com>
Date: Sat, 16 Mar 2024 16:48:38 +1100
Subject: [PATCH 12/12] experiment with ptr concept for arguments

---
 bindgen/c.ml            | 20 ++++++++++++++------
 bindgen/caml.ml         |  2 +-
 bindgen/codegen.ml      | 32 ++++++++++++++++++++++++++------
 bindgen/dunefile.ml     |  2 +-
 bindgen/experimental.ml | 19 -------------------
 bindgen/ir.ml           |  8 +++++++-
 bindgen/runtime.ml      | 20 ++++++++++++++++++++
 examples/caml_doggo.c   | 24 +++++++++++++++++++++++-
 examples/doggo.c        | 11 +++++++----
 examples/doggo.h        |  7 +++----
 examples/doggo.ml       | 19 -------------------
 examples/doggo_sys.ml   | 23 +++++++++++++++++++++++
 examples/dune           | 12 ++++--------
 examples/main.ml        | 20 +++++++-------------
 14 files changed, 136 insertions(+), 83 deletions(-)
 delete mode 100644 bindgen/experimental.ml
 create mode 100644 bindgen/runtime.ml
 delete mode 100644 examples/doggo.ml
 create mode 100644 examples/doggo_sys.ml

diff --git a/bindgen/c.ml b/bindgen/c.ml
index cbee800..990638c 100644
--- a/bindgen/c.ml
+++ b/bindgen/c.ml
@@ -190,12 +190,20 @@ module Shims = struct
             List.map
               (fun (name, param_type) ->
                 let c_type = ctype_of_ir param_type in
-                let c_type_name = ctype_name c_type in
-                decl c_type name
-                  (Some
-                     (call
-                        (caml_ ^ c_type_name ^ "_of_value")
-                        [ var (caml_ ^ name) ])))
+                match c_type with
+                | Ptr _t ->
+                    let _c_type_name = ctype_name c_type in
+                    decl c_type name
+                      (Some
+                         (call "Nativeint_val"
+                            [ call "Field" [ var (caml_ ^ name); int 1 ] ]))
+                | _ ->
+                    let c_type_name = ctype_name c_type in
+                    decl c_type name
+                      (Some
+                         (call
+                            (caml_ ^ c_type_name ^ "_of_value")
+                            [ var (caml_ ^ name) ])))
               fn_params
           in
 
diff --git a/bindgen/caml.ml b/bindgen/caml.ml
index 9de625a..b1821b5 100644
--- a/bindgen/caml.ml
+++ b/bindgen/caml.ml
@@ -32,7 +32,7 @@ let rec core_type_from_ir typ =
   | Ir.Prim Bool -> Typ.constr (lid "bool") []
   | Ir.Prim Char -> Typ.constr (lid "char") []
   | Ir.Prim Void -> Typ.constr (lid "unit") []
-  | Ir.Ptr t -> Typ.constr (lid "ptr") [(core_type_from_ir t)]
+  | Ir.Ptr t -> Typ.constr (lid "cptr") [ core_type_from_ir t ]
   | Ir.Func { fn_ret; fn_params } -> (
       match fn_params with
       | [] ->
diff --git a/bindgen/codegen.ml b/bindgen/codegen.ml
index a974ef5..a46b595 100644
--- a/bindgen/codegen.ml
+++ b/bindgen/codegen.ml
@@ -5,8 +5,7 @@ let with_file file fn =
   close_out oc;
   ()
 
-let read_file file =
-  In_channel.with_open_bin file In_channel.input_all
+let read_file file = In_channel.with_open_bin file In_channel.input_all
 
 let write_dune_file (dune : Dunefile.t) =
   with_file "dune" @@ fun fmt ->
@@ -25,14 +24,35 @@ let write_dune_file (dune : Dunefile.t) =
   Format.fprintf fmt "\n%!"
 
 let write_caml_files caml (dune : Dunefile.t) =
-  let experimental = read_file "../bindgen/experimental.ml" in
+  let runtime_ocaml = read_file "../bindgen/runtime.ml" in
   with_file dune.caml_file_name @@ fun fmt ->
   Format.fprintf fmt "(* automatically generated by ocaml-bindgen 0.0.1 *)\n";
-  (* Format.fprintf fmt "open Bindgen.Experimental\n"; *)
-  Format.fprintf fmt "%s\n" experimental;
+  Format.fprintf fmt "%s\n" runtime_ocaml;
   Format.fprintf fmt "%s\n%!" (Format.asprintf "%a" Pprintast.structure caml)
 
 let write_c_files (c : C.program) (dune : Dunefile.t) =
   with_file dune.c_file_name @@ fun fmt ->
   Format.fprintf fmt "/* automatically generated by ocaml-bindgen 0.0.1 */\n";
-  Format.fprintf fmt "%s\n%!" (Format.asprintf "%a" C.pp c)
+  Format.fprintf fmt "\n%s\n%!" (Format.asprintf "%a" C.pp c);
+  Format.fprintf fmt
+    {|#include <stdlib.h>
+value bindgen_alloc(value caml_size) {
+    CAMLparam1(caml_size);
+
+    // Convert OCaml integer to C size
+    size_t size = Int_val(caml_size);
+    printf("Allocated size %%ld \n", size);
+
+    void* ptr = malloc(sizeof(size));
+    if (ptr == NULL) {
+        // TODO: handle allocation failure
+        CAMLreturn(Val_unit);
+    }
+    
+    // Wrap the pointer as an OCaml value
+    CAMLreturn(caml_copy_nativeint(ptr));
+}
+
+void bindgen_free(value caml_addr) {
+    free(Nativeint_val(caml_addr));
+} |}
diff --git a/bindgen/dunefile.ml b/bindgen/dunefile.ml
index 4ea3f3e..3caedd7 100644
--- a/bindgen/dunefile.ml
+++ b/bindgen/dunefile.ml
@@ -3,6 +3,6 @@ type t = { lib_name : string; caml_file_name : string; c_file_name : string }
 let from_ir (ir : Ir.t) : t =
   {
     lib_name = ir.lib_name;
-    caml_file_name = ir.lib_name ^ ".ml";
+    caml_file_name = ir.lib_name ^ "_sys" ^ ".ml";
     c_file_name = "caml_" ^ ir.lib_name ^ ".c";
   }
diff --git a/bindgen/experimental.ml b/bindgen/experimental.ml
deleted file mode 100644
index 9553fe9..0000000
--- a/bindgen/experimental.ml
+++ /dev/null
@@ -1,19 +0,0 @@
-type lifetime =
-  Function (** The value can live for the lifetime of the function call, which upon return will signal that the 
-               value can be dropped (finalizer?) *)
-  | Ocaml  (** The value is managed by the OCaml runtime *)
-  | C      (** The value is allocated and passed to C which is then in charge of cleaning it up *)
-
-type 'a ptr = {
-  lifetime: lifetime;
-  value: 'a;
-}
-
-(* The easiest way to call a function that requires a int ptr is to do *)
-
-(* basically we need a funtion
-  string -> char ptr that we can then pass to the function   
-*)
-
-
-(* let char_ptr (s: string) : char ptr = {} *)
\ No newline at end of file
diff --git a/bindgen/ir.ml b/bindgen/ir.ml
index f484931..6c052f9 100644
--- a/bindgen/ir.ml
+++ b/bindgen/ir.ml
@@ -20,7 +20,7 @@ module Lift = struct
     match name with Clang.Ast.IdentifierName x -> x | _ -> assert false
 
   let rec lift_type (typ : Clang.Type.t) =
-    Format.printf "lift_type: %S\n" (Clang.Type.show typ); flush stdout;
+    (* Format.printf "lift_type: %S\n" (Clang.Type.show typ); flush stdout; *)
     match typ.desc with
     | Clang.Ast.BuiltinType Int -> Prim Int
     | Clang.Ast.BuiltinType Float -> Prim Float
@@ -106,3 +106,9 @@ module Lift = struct
 end
 
 let lift = Lift.lift
+
+let string_of_prim prim =
+  match prim with
+  | Int -> "Int"
+  | Char -> "Char"
+  | Float | Bool | Void -> "Other (TODO)"
diff --git a/bindgen/runtime.ml b/bindgen/runtime.ml
new file mode 100644
index 0000000..75acbcf
--- /dev/null
+++ b/bindgen/runtime.ml
@@ -0,0 +1,20 @@
+type lifetime =
+  | Function
+      (** The value can live for the lifetime of the function call, which upon return will signal that the 
+               value can be dropped (finalizer?) *)
+  | Ocaml  (** The value is managed by the OCaml runtime *)
+  | C
+      (** The value is allocated and passed to C which is then in charge of cleaning it up *)
+
+type 'a cptr = { lifetime : lifetime; addr : nativeint }
+
+external bindgen_alloc : size:int -> nativeint = "bindgen_alloc"
+external bindgen_free : nativeint -> unit = "bindgen_free"
+
+let sizeof _ = 4 (* TODO: how to handle different types? *)
+
+let create_ptr (value : 'a) : 'a cptr =
+  let addr = bindgen_alloc ~size:(sizeof value) in
+  print_endline ("Addr: " ^ Nativeint.to_string addr);
+  Gc.finalise bindgen_free addr;
+  { lifetime = Ocaml; addr }
diff --git a/examples/caml_doggo.c b/examples/caml_doggo.c
index 90cd74a..cb7e28b 100644
--- a/examples/caml_doggo.c
+++ b/examples/caml_doggo.c
@@ -1,4 +1,5 @@
 /* automatically generated by ocaml-bindgen 0.0.1 */
+
 #include "doggo.h"
 #include <caml/alloc.h>
 #include <caml/callback.h>
@@ -8,9 +9,30 @@
 #include <caml/unixsupport.h>
 void caml_print_age(value caml_age) {
   CAMLparam1(caml_age);
-  int* age = caml_int_of_value(caml_age);
+  int* age = Nativeint_val(Field(caml_age, 1));
   print_age(age);
   CAMLreturn0;
 }
 
 
+#include <stdlib.h>
+value bindgen_alloc(value caml_size) {
+    CAMLparam1(caml_size);
+
+    // Convert OCaml integer to C size
+    size_t size = Int_val(caml_size);
+    printf("Allocated size %ld \n", size);
+
+    void* ptr = malloc(sizeof(size));
+    if (ptr == NULL) {
+        // TODO: handle allocation failure
+        CAMLreturn(Val_unit);
+    }
+    
+    // Wrap the pointer as an OCaml value
+    CAMLreturn(caml_copy_nativeint(ptr));
+}
+
+void bindgen_free(value caml_addr) {
+    free(Nativeint_val(caml_addr));
+} 
\ No newline at end of file
diff --git a/examples/doggo.c b/examples/doggo.c
index 473d63b..9f1fe0a 100644
--- a/examples/doggo.c
+++ b/examples/doggo.c
@@ -21,7 +21,10 @@
 void print_age(int* age) {
   printf("Age: %d\n", *age);
 }
-
-// void greet_dog(char* dog_name) {
-//   printf("Hey %s\n", dog_name);
-// }
\ No newline at end of file
+// void print_name(char* name) {
+//   printf("Name: %s\n", name);
+// }
+// void print_doggo(Doggo *dog) {
+//   printf("wow: %c\n", dog->wow);
+//   print_age(&dog->many);
+// }
diff --git a/examples/doggo.h b/examples/doggo.h
index 128c42d..c241b6d 100644
--- a/examples/doggo.h
+++ b/examples/doggo.h
@@ -7,14 +7,13 @@
 
 // typedef struct Doggo {
 //     int many;
-//     breed breed;
+//     // breed breed;
 //     char wow;
 //     float weight;
 // } Doggo;
 
 // void eleven_out_of_ten_majestic_af(Doggo* pupper);
 
-// void no_input_no_output(void);
-
 void print_age(int* age);
-// void greet_dog(char* dog_name);
\ No newline at end of file
+// void print_name(char* name);
+// void print_doggo(Doggo *dog);
\ No newline at end of file
diff --git a/examples/doggo.ml b/examples/doggo.ml
deleted file mode 100644
index d4ffa20..0000000
--- a/examples/doggo.ml
+++ /dev/null
@@ -1,19 +0,0 @@
-(* automatically generated by ocaml-bindgen 0.0.1 *)
-type lifetime =
-  Function (** The value can live for the lifetime of the function call, which upon return will signal that the 
-               value can be dropped (finalizer?) *)
-  | Ocaml  (** The value is managed by the OCaml runtime *)
-  | C      (** The value is allocated and passed to C which is then in charge of cleaning it up *)
-
-type 'a ptr = {
-  lifetime: lifetime;
-  value: 'a;
-}
-
-(* basically we need a funtion
-  string -> char ptr that we can then pass to the function   
-*)
-
-
-(* let char_ptr (s: string) : char ptr = {} *)
-external print_age : age:int ptr -> unit = "caml_print_age"
diff --git a/examples/doggo_sys.ml b/examples/doggo_sys.ml
new file mode 100644
index 0000000..7882677
--- /dev/null
+++ b/examples/doggo_sys.ml
@@ -0,0 +1,23 @@
+(* automatically generated by ocaml-bindgen 0.0.1 *)
+type lifetime =
+  | Function
+      (** The value can live for the lifetime of the function call, which upon return will signal that the 
+               value can be dropped (finalizer?) *)
+  | Ocaml  (** The value is managed by the OCaml runtime *)
+  | C
+      (** The value is allocated and passed to C which is then in charge of cleaning it up *)
+
+type 'a cptr = { lifetime : lifetime; addr : nativeint }
+
+external bindgen_alloc : size:int -> nativeint = "bindgen_alloc"
+external bindgen_free : nativeint -> unit = "bindgen_free"
+
+let sizeof _ = 4 (* TODO: how to handle different types? *)
+
+let create_ptr (value : 'a) : 'a cptr =
+  let addr = bindgen_alloc ~size:(sizeof value) in
+  print_endline ("Addr: " ^ Nativeint.to_string addr);
+  Gc.finalise bindgen_free addr;
+  { lifetime = Ocaml; addr }
+
+external print_age : age:int cptr -> unit = "caml_print_age"
diff --git a/examples/dune b/examples/dune
index 6f247d7..aedeb7c 100644
--- a/examples/dune
+++ b/examples/dune
@@ -1,6 +1,6 @@
 (executable
-  (name main)
-  (libraries bindgen)
+ (name main)
+ (libraries bindgen)
  (foreign_stubs
   (language c)
   (names doggo caml_doggo)
@@ -9,13 +9,9 @@
 
 (rule
  (alias all)
- (targets
-   doggo.ml
-   caml_doggo.c
-  )
+ (targets doggo_sys.ml caml_doggo.c)
  (deps doggo.h)
  (action
-  (run
-   %{bin:ocaml-bindgen} doggo.h doggo))
+  (run %{bin:ocaml-bindgen} doggo.h doggo))
  (mode
   (promote (until-clean))))
diff --git a/examples/main.ml b/examples/main.ml
index b1a6565..53cb9e6 100644
--- a/examples/main.ml
+++ b/examples/main.ml
@@ -1,16 +1,10 @@
-open Doggo
+(* open Doggo *)
 
-(* let pupper = {
-  many=2112;
-  wow='x';
-  breed=C_Labrador;
-  weight=18.9;
-}
+module Doggo = struct
+  include Doggo_sys
+  (** Here is where we would write our wrappers around the raw bindings *)
 
-let () =
-  Doggo.eleven_out_of_ten_majestic_af ~pupper *)
+  let wrapper_print_age (age : int) = print_age ~age:(create_ptr age)
+end
 
-let char_ptr_of_string = 
-
-let () =
-  greet_dog ~dog_name:"Puppy"
\ No newline at end of file
+let () = Doggo.wrapper_print_age 25