2016 Update

Task/Tokenize-a-string/OCaml/tokenize-a-string-1.ocaml

@@ -1,7 +1,2 @@
-let rec split_char sep str =
-  try
-    let i = String.index str sep in
-    String.sub str 0 i ::
-      split_char sep (String.sub str (i+1) (String.length str - i - 1))
-  with Not_found ->
-    [str]
+let words = String.split_on_char ',' "Hello,How,Are,You,Today" in
+String.concat "." words

Task/Tokenize-a-string/OCaml/tokenize-a-string-2.ocaml

@@ -1,18 +1,10 @@
-(* [try .. with] structures break tail-recursion,
-   so we externalise it in a sub-function *)
-let string_index str c =
-  try Some(String.index str c)
-  with Not_found -> None
-
-let split_char sep str =
-  let rec aux acc str =
-    match string_index str sep with
-    | Some i ->
-        let this = String.sub str 0 i
-        and next = String.sub str (i+1) (String.length str - i - 1) in
-        aux (this::acc) next
-    | None ->
-        List.rev(str::acc)
-  in
-  aux [] str
-;;
+let split_on_char sep s =
+  let r = ref [] in
+  let j = ref (String.length s) in
+  for i = String.length s - 1 downto 0 do
+    if s.[i] = sep then begin
+      r := String.sub s (i + 1) (!j - i - 1) :: !r;
+      j := i
+    end
+  done;
+  String.sub s 0 !j :: !r