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Date: Fri, 04 Jan 2008 19:09:57 +0900 (JST)
Message-Id: <20080104.190957.68544872.keiko@kurims.kyoto-u.ac.jp>
To: shawjef3@msu.edu
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] restricting and hiding record fields for functors
From: Keiko Nakata <keiko@kurims.kyoto-u.ac.jp>
In-Reply-To: <477DED41.3040009@msu.edu>
References: <477DED41.3040009@msu.edu>
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X-Spam: no; 0.00; restricting:01 functors:01 ocaml:01 struct:01 sig:01 val:01 struct:01 syntax:01 ocaml:01 caml-list:01 int:01 int:01 caml:02 garrigue:03 module:03 

Hello.

Maybe private row types are useful to you;
see the Language extensions section of the OCaml manual:
http://caml.inria.fr/pub/docs/manual-ocaml/manual021.html

You can do something like this:

  module M = struct
    type t = < x:int; y:int>
    let r = object method x = 1 method y = 2 end
  end;;
  
  module F(X:sig type t = private <x:int; ..> val r: t end) = 
    struct  let x = X.r#x  end;;
  
  module FM = F(M);;
  let x = FM.x;;


I often prefer to use a syntax extension,
found at http://www.math.nagoya-u.ac.jp/~garrigue/code/ocaml.html,
which allows me to write

  let r = {| x = 1 method y = 2 |}

instead of 

  let r = object method x = 1 method y = 2 end


With best regards,
Keiko