On Friday 09 February 2007 21:55, Brian Hurt wrote:
> let rec amb = function
>
>     | [] -> None
>     | h :: t ->
>
>        let r =
>           try
>              Some(h ())
>           with
>
>              | _ -> None
>
>        in
>        match r with
>
>        | None -> amb t
>        | Some(_) as e -> e
>
> As a slightly better implementation.

I think you're trying to box the returned value in order to evade non-tail 
recursion but the OPs function was actually already tail recursive because 
the recursive call to "amb" occurs outside the try..with.

-- 
Dr Jon D Harrop, Flying Frog Consultancy Ltd.
OCaml for Scientists
http://www.ffconsultancy.com/products/ocaml_for_scientists