> Agreed - though [find] is one of the examples where you do need find and
> find_exc - because often there are occasions where before calling
> {Map,Set,Hashtbl}.find you already know that the key exists and so won't
> fail at which point the 'a option boxing is a waste of time and space and
> Not_found would be a truly exceptional situation so passes the previously
> mentioned test.

In that case what you want is an alternate function "really_find" that
doesn't raise Not_found but Invalid_argument if the key cannot be
found.

Best,

Daniel