- <pre>
- # let ( * ) m f = match m with None -> None | Some n -> f n;;
- val ( * ) : 'a option -> ('a -> 'b option) -> 'b option = <fun>
- # let unit x = Some x;;
- val unit : 'a -> 'a option = <fun>
- # unit 2 * unit;;
- - : int option = Some 2
- </pre>
+<pre>
+# let ( * ) m f = match m with None -> None | Some n -> f n;;
+val ( * ) : 'a option -> ('a -> 'b option) -> 'b option = <fun>
+# let unit x = Some x;;
+val unit : 'a -> 'a option = <fun>
+# unit 2 * unit;;
+- : int option = Some 2
+</pre>