Re: [Caml-list] Multiparameter functors?

[Julien Demouth <julien.demouth@free.fr>]

Hi,

Brian Hurt wrote:
> Is it possible to do multi-parameter functors?  What I want to be able to 
> so is something like:
> 
> module Make(Key: Map.OrderedType, Pri: Map.OrderedType) = struct
> 	type key = Key.t;;
> 	type pri = Pri.t;;
> 	...
> end;;

Of course it's possible but you mustn't use the comma. A functor is just 
a function. The only difference is that it deals with structure whereas 
"normal" functions deal with values. Consider the following example:

module type M = sig type t end

module type N = sig type t end

module type R = sig type u and v end

module Make (U:M) (V:N) : R with type u = U.t and type v = V.t

> Am I being stupid and just missing something obvious, or is there some 
> subtle reason why I shouldn't be doing this?

Every question is good to be asked ;)

Regards,

Julien


-------------------
To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr
Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners