Re: [Caml-list] Stupid question re:modules

[Vincent Aravantinos <vincent.aravantinos@yahoo.fr>]

Le 24 août 07 à 02:32, Brian Hurt a écrit :
>
> I should just know this.  So let's say I have two module types  
> defined:
>
> module type Foo = sig
> 	type 'a t
> 	val foo : 'a -> 'a t
> end;;
>
> module type Bar = sig
> 	type 'a t
> 	val bar : 'a -> 'a t
> end;;
>
> Now, I want to define a module that is both a Foo and a Bar without  
> cutting and pasting the module definitions around.  I've been  
> trying to do:
>
> module Baz : sig
> 	type 'a baz
> 	include Foo with type 'a t = 'a baz
> 	include Bar with type 'a t = 'a baz
> end;;
>
> but this blows up on the Bar line (multiple definitions of 'a t).
>
> There is a solution to this, I'm just being stupid and forgetting  
> what it is.  Hints would be appreciated.
>
> Brian

See also :
  http://caml.inria.fr/pub/ml-archives/caml-list/2006/12/ 
c7461312202053f2213a9bb33206fcb8.en.html

BTW, I thought there was some kind of research about inheritance and  
modules (heard about "mixin modules"), is there any plan to implement  
this one day in ocaml ?

The lack of real inheritance with modules is a major restriction IMHO...




--
Vincent Aravantinos
PhD Student - LIG - CAPP Team