copied from js_of_ocaml/toplevel/examples/lwt_toplevel

colorize.fake.ml

@@ -0,0 +1,28 @@
+open Js_of_ocaml
+open Js_of_ocaml_tyxml
+
+let text ~a_class:cl s = Tyxml_js.Html.(span ~a:[ a_class [ cl ] ] [ txt s ])
+
+let ocaml = text
+
+let highlight from_ to_ e =
+  match Js.Opt.to_option e##.textContent with
+  | None -> assert false
+  | Some x ->
+      let x = Js.to_string x in
+      let (`Pos from_) = from_ in
+      let to_ =
+        match to_ with
+        | `Pos n -> n
+        | `Last -> String.length x - 1
+      in
+      e##.innerHTML := Js.string "";
+      let span kind s =
+        if s <> ""
+        then
+          let span = Tyxml_js.Html.(span ~a:[ a_class [ kind ] ] [ txt s ]) in
+          Dom.appendChild e (Tyxml_js.To_dom.of_element span)
+      in
+      span "normal" (String.sub x 0 from_);
+      span "errorloc" (String.sub x from_ (to_ - from_));
+      span "normal" (String.sub x to_ (String.length x - to_))