I meant something along the lines of

```ocaml
let get_string = function
  | None -> "None"
  | Some s -> Printf.sprintf "Some %S" s
```

or, if 'maybe' would be defined somewhere in general (OTOH):

```ocaml
let maybe v f = function
  | None -> v
  | Some v' -> f v'

let get_string = maybe "None" (Printf.sprintf "Some %S")
```