move demo documents into separate files

demo/docs/ocaml.ml

@@ -0,0 +1,18 @@
+(*
+ * Example of early return implementation taken from
+ * http://ocaml.janestreet.com/?q=node/91
+ *)
+
+let with_return (type t) (f : _ -> t) =
+  let module M =
+     struct exception Return of t end
+  in
+  let return = { return = (fun x -> raise (M.Return x)); } in
+  try f return with M.Return x -> x
+
+
+(* Function that uses the 'early return' functionality provided by `with_return` *)
+let sum_until_first_negative list =
+  with_return (fun r ->
+    List.fold list ~init:0 ~f:(fun acc x ->
+      if x >= 0 then acc + x else r.return acc))