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Date: Mon, 14 Jun 2004 23:48:27 +0900 (JST)
Message-Id: <20040614.234827.74677774.keiko@kaba.or.jp>
To: IdeFX@Iname.com
Cc: caml-list@inria.fr, keiko@kaba.or.jp
Subject: Re: [Caml-list] troubles with polymorphic variant in class
From: nakata keiko <keiko@kaba.or.jp>
In-Reply-To: <1087142756.10383.50.camel@Bess>
References: <1087142756.10383.50.camel@Bess>
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I hope this would be of some help.

module type Ct = sig type t end

module type Crec =
  sig
    module T : Ct
    class button : object method add_child : T.t -> unit end
  end

module COt(Crec : Crec) = 
  struct type t = [`Whatever|`Button of Crec.button] 
  end

module CO(Crec : Crec) =
  struct
    module T = COt(Crec)
    class button =
      object
        val mutable children : T.t list = [`Whatever]
        method add_child x = children <- x::children
      end
  end
module rec X : (Crec with module T = COt(X)) = CO(X)

As I done, you can specify the type of elements of the list "children"
inside "COt".
The above code is taken from 
http://caml.inria.fr/archives/200403/msg00344.html

with best regards.

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