diff --git a/lib/dune b/lib/dune
index b0e061b..8b69147 100644
--- a/lib/dune
+++ b/lib/dune
@@ -2,6 +2,7 @@
  (public_name pretty_expressive)
  (name pretty_expressive)
  (modules (:standard \ prelude))
+ ; (libraries batteries)
  (modules_without_implementation signature))
 
 (mdx (files :standard *.mli)
diff --git a/lib/printer.ml b/lib/printer.ml
index 5178cdf..14c3ff9 100644
--- a/lib/printer.ml
+++ b/lib/printer.ml
@@ -341,6 +341,7 @@ module MakeCompat (C : Signature.CostFactory): (Signature.PrinterCompatT with ty
   let (<>) = (^^)
 end
 
+(* $MDX part-begin=default_cost_factory *)
 let default_cost_factory ~page_width ?computation_width () =
   (module struct
     type t = int * int
@@ -369,3 +370,4 @@ let default_cost_factory ~page_width ?computation_width () =
     let debug (o, h) = Printf.sprintf "(%d %d)" o h
 
   end: Signature.CostFactory with type t = int * int)
+(* $MDX part-end *)
diff --git a/lib/printer.mli b/lib/printer.mli
index 3a167d5..ad4ecba 100644
--- a/lib/printer.mli
+++ b/lib/printer.mli
@@ -23,33 +23,33 @@ val default_cost_factory : page_width:int -> ?computation_width:int -> unit ->
 
     Internally, [default_cost_factory] is defined as:
 
-    {@ocaml skip[
-    let default_cost_factory ~page_width ?computation_width () =
-      (module struct
-        type t = int * int
-        let limit = match computation_width with
-          | None -> (float_of_int page_width) *. 1.2 |> int_of_float
-          | Some computation_width -> computation_width
-
-        let text pos len =
-          let stop = pos + len in
-          if stop > page_width then
-            let maxwc = max page_width pos in
-            let a = maxwc - page_width in
-            let b = stop - maxwc in
-            (b * (2*a + b), 0)
-          else
-            (0, 0)
-
-        let newline _ = (0, 1)
-
-        let combine (o1, h1) (o2, h2) =
-          (o1 + o2, h1 + h2)
-
-        let le (o1, h1) (o2, h2) =
-          if o1 = o2 then h1 <= h2 else o1 < o2
-
-        let debug (o, h) = Printf.sprintf "(%d %d)" o h
-
-      end: Signature.CostFactory with type t = int * int)
-    ]} *)
+    {@ocaml file=printer.ml,part=default_cost_factory[
+let default_cost_factory ~page_width ?computation_width () =
+  (module struct
+    type t = int * int
+    let limit = match computation_width with
+      | None -> (float_of_int page_width) *. 1.2 |> int_of_float
+      | Some computation_width -> computation_width
+
+    let text pos len =
+      let stop = pos + len in
+      if stop > page_width then
+        let maxwc = max page_width pos in
+        let a = maxwc - page_width in
+        let b = stop - maxwc in
+        (b * (2*a + b), 0)
+      else
+        (0, 0)
+
+    let newline _ = (0, 1)
+
+    let combine (o1, h1) (o2, h2) =
+      (o1 + o2, h1 + h2)
+
+    let le (o1, h1) (o2, h2) =
+      if o1 = o2 then h1 <= h2 else o1 < o2
+
+    let debug (o, h) = Printf.sprintf "(%d %d)" o h
+
+  end: Signature.CostFactory with type t = int * int)
+]} *)
diff --git a/test/pretty_expressive.ml b/test/pretty_expressive.ml
index b309bae..3a228c1 100644
--- a/test/pretty_expressive.ml
+++ b/test/pretty_expressive.ml
@@ -30,42 +30,42 @@ let print_doc_group (w : int) =
 let test_choice_doc_80 () =
   Alcotest.(check string) "same string"
     (String.concat "\n"
-       [ "while (true) {"
-       ; "    f();"
-       ; "    if (done()) exit();"
-       ; "}"
+       [ "while (true) {" ;
+         "    f();" ;
+         "    if (done()) exit();" ;
+         "}"
        ])
     (print_doc_choice 80)
 
 let test_choice_doc_20 () =
   Alcotest.(check string) "same string"
     (String.concat "\n"
-       [ "while (true) {"
-       ; "    f();"
-       ; "    if (done())"
-       ; "        exit();"
-       ; "}"
+       [ "while (true) {" ;
+         "    f();" ;
+         "    if (done())" ;
+         "        exit();" ;
+         "}"
        ])
     (print_doc_choice 20)
 
 let test_group_doc_80 () =
   Alcotest.(check string) "same string"
     (String.concat "\n"
-       [ "while (true) {"
-       ; "    f();"
-       ; "    if (done()) exit();"
-       ; "}"
+       [ "while (true) {" ;
+         "    f();" ;
+         "    if (done()) exit();" ;
+         "}"
        ])
     (print_doc_group 80)
 
 let test_group_doc_20 () =
   Alcotest.(check string) "same string"
     (String.concat "\n"
-       [ "while (true) {"
-       ; "    f();"
-       ; "    if (done())"
-       ; "        exit();"
-       ; "}"
+       [ "while (true) {" ;
+         "    f();" ;
+         "    if (done())" ;
+         "        exit();" ;
+         "}"
        ])
     (print_doc_group 20)
 
@@ -101,19 +101,19 @@ let example_sexp = List [Atom "a"; Atom "b"; Atom "c"; Atom "d"]
 let test_sexp_4 () =
   Alcotest.(check string) "same string"
     (String.concat "\n"
-       [ "(a"
-       ; " b"
-       ; " c"
-       ; " d)"
+       [ "(a" ;
+         " b" ;
+         " c" ;
+         " d)"
        ])
     (print_sexp example_sexp 4)
 
 let test_sexp_6 () =
   Alcotest.(check string) "same string"
     (String.concat "\n"
-       [ "(a b"
-       ; "   c"
-       ; "   d)"
+       [ "(a b" ;
+         "   c" ;
+         "   d)"
        ])
     (print_sexp example_sexp 6)
 
@@ -124,13 +124,13 @@ let test_sexp_10 () =
     (print_sexp example_sexp 10)
 
 let suite =
-  [ "choice; w = 80", `Quick, test_choice_doc_80
-  ; "choice; w = 20", `Quick, test_choice_doc_20
-  ; "group; w = 80", `Quick, test_group_doc_80
-  ; "group; w = 20", `Quick, test_group_doc_20
-  ; "sexp; w = 4", `Quick, test_sexp_4
-  ; "sexp; w = 6", `Quick, test_sexp_6
-  ; "sexp; w = 10", `Quick, test_sexp_10
+  [ "choice; w = 80", `Quick, test_choice_doc_80 ;
+    "choice; w = 20", `Quick, test_choice_doc_20 ;
+    "group; w = 80", `Quick, test_group_doc_80 ;
+    "group; w = 20", `Quick, test_group_doc_20 ;
+    "sexp; w = 4", `Quick, test_sexp_4 ;
+    "sexp; w = 6", `Quick, test_sexp_6 ;
+    "sexp; w = 10", `Quick, test_sexp_10
   ]
 
 let () =