diff --git a/src/jbuild_load.ml b/src/jbuild_load.ml
index 67dd1070..6e33c073 100644
--- a/src/jbuild_load.ml
+++ b/src/jbuild_load.ml
@@ -171,9 +171,48 @@ type conf =
   ; scopes    : Scope_info.t list
   }
 
+module Sexp_io = struct
+  open Sexp
+
+  let ocaml_script_prefix = "(* -*- tuareg -*- *)"
+  let ocaml_script_prefix_len = String.length ocaml_script_prefix
+
+  type sexps_or_ocaml_script =
+    | Sexps of Ast.t list
+    | Ocaml_script
+
+  let load_many_or_ocaml_script fname =
+    Io.with_file_in fname ~f:(fun ic ->
+      let state = Parser.create ~fname ~mode:Many in
+      let buf = Bytes.create buf_len in
+      let rec loop stack =
+        match input ic buf 0 buf_len with
+        | 0 -> Parser.feed_eoi state stack
+        | n -> loop (Parser.feed_subbytes state buf ~pos:0 ~len:n stack)
+      in
+      let rec loop0 stack i =
+        match input ic buf i (buf_len - i) with
+        | 0 ->
+          let stack = Parser.feed_subbytes state buf ~pos:0 ~len:i stack in
+          Sexps (Parser.feed_eoi state stack)
+        | n ->
+          let i = i + n in
+          if i < ocaml_script_prefix_len then
+            loop0 stack i
+          else if Bytes.sub_string buf 0 ocaml_script_prefix_len
+                    [@warning "-6"]
+                  = ocaml_script_prefix then
+            Ocaml_script
+          else
+            let stack = Parser.feed_subbytes state buf ~pos:0 ~len:i stack in
+            Sexps (loop stack)
+      in
+      loop0 Parser.Stack.empty 0)
+end
+
 let load ~dir ~scope ~ignore_promoted_rules =
   let file = Path.relative dir "jbuild" in
-  match Sexp.load_many_or_ocaml_script (Path.to_string file) with
+  match Sexp_io.load_many_or_ocaml_script (Path.to_string file) with
   | Sexps sexps ->
     Jbuilds.Literal (dir, scope,
                      Stanzas.parse scope sexps ~file
diff --git a/src/stdune/sexp.ml b/src/stdune/sexp.ml
index f30bbe52..7ace78e5 100644
--- a/src/stdune/sexp.ml
+++ b/src/stdune/sexp.ml
@@ -21,41 +21,6 @@ let load_many_as_one ~fname =
     let loc = { (Ast.loc x) with stop = (Ast.loc last).stop } in
     Ast.List (loc, x :: l)
 
-let ocaml_script_prefix = "(* -*- tuareg -*- *)"
-let ocaml_script_prefix_len = String.length ocaml_script_prefix
-
-type sexps_or_ocaml_script =
-  | Sexps of Ast.t list
-  | Ocaml_script
-
-let load_many_or_ocaml_script fname =
-  Io.with_file_in fname ~f:(fun ic ->
-    let state = Parser.create ~fname ~mode:Many in
-    let buf = Bytes.create buf_len in
-    let rec loop stack =
-      match input ic buf 0 buf_len with
-      | 0 -> Parser.feed_eoi state stack
-      | n -> loop (Parser.feed_subbytes state buf ~pos:0 ~len:n stack)
-    in
-    let rec loop0 stack i =
-      match input ic buf i (buf_len - i) with
-      | 0 ->
-        let stack = Parser.feed_subbytes state buf ~pos:0 ~len:i stack in
-        Sexps (Parser.feed_eoi state stack)
-      | n ->
-        let i = i + n in
-        if i < ocaml_script_prefix_len then
-          loop0 stack i
-        else if Bytes.sub_string buf 0 ocaml_script_prefix_len
-                  [@warning "-6"]
-                = ocaml_script_prefix then
-          Ocaml_script
-        else
-          let stack = Parser.feed_subbytes state buf ~pos:0 ~len:i stack in
-          Sexps (loop stack)
-    in
-    loop0 Parser.Stack.empty 0)
-
 module type Combinators = sig
   type 'a t
   val unit       : unit                      t
diff --git a/src/stdune/sexp.mli b/src/stdune/sexp.mli
index b4cb16fb..d1a2d49c 100644
--- a/src/stdune/sexp.mli
+++ b/src/stdune/sexp.mli
@@ -3,12 +3,6 @@ include module type of struct include Usexp end with module Loc := Usexp.Loc
 val load : fname:string -> mode:'a Parser.Mode.t -> 'a
 val load_many_as_one : fname:string -> Ast.t
 
-type sexps_or_ocaml_script =
-  | Sexps of Ast.t list
-  | Ocaml_script
-
-val load_many_or_ocaml_script : string -> sexps_or_ocaml_script
-
 module type Combinators = sig
   type 'a t
   val unit       : unit                      t
@@ -161,3 +155,7 @@ module Of_sexp : sig
 
   val enum : (string * 'a) list -> 'a t
 end
+
+(**/**)
+(* used in jbuild_load *)
+val buf_len : int