On Wed, 25 Jul 2007, cultural_sublimation wrote:
> My question is the following: how do I undo the unification of movie_t
> and actor_t, so that externally, the signatures of these functions are
> different? (listed below). I don't want the caller to be bothering
> with matches, and quite frankly, the fact that movie_t and actor_t were
> unified is an implementation detail, used only to avoid the duplication
> of the process_query code.
>
>
> val process_movies : string array array -> movie_t array
> val process_actors : string array array -> actor_t array
Well, unfortunately, if the output of the same function, you're out of
luck, as they have to share the same output type. You'd need to offer up
a set of refinement functions for each of the cases you want to separate
out, e.g.
let refine_movie = function Movie m -> m | _ -> assert false;;
let refine_actor = function Actor a -> a | _ -> assert false;;
and so on.
I know it's not what you want, but unless you do a lot more work to hide
the way the type system works in OCaml, you're stuck with it, as you won't
be able to come up with a useful function of type string array array -> 'a
array, which is what you're asking for.
William D. Neumannn
---
"There's just so many extra children, we could just feed the
children to these tigers. We don't need them, we're not doing
anything with them.
Tigers are noble and sleek; children are loud and messy."
-- Neko Case
Life is unfair. Kill yourself or get over it.
-- Black Box Recorder
