Jon Harrop wrote:
> On Monday 06 November 2006 21:15, Serge Aleynikov wrote:

>> Could anyone point at a suitable resource?

> I wasn't even aware that you could add type annotations inside a pattern.

> Your
> example will not work simply because OCaml's type system will not allow float
> to unify with string. You need some context where type inference will allow
> different possibilities, like a tuple containing both a float and a string:

> # let f = function
>   | (y : float), _ -> print_float y
>   | _, (s : string) -> print_string s;;

> or a polymorphic variant containing either a float or a string:

> # let f = function
>   | `F (y : float) -> print_float y
>   | `S (s : string) -> print_string s;;
> val f : [< `F of float | `S of string ] -> unit = <fun>