From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <garrigue@math.nagoya-u.ac.jp>
Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78])
	by yquem.inria.fr (Postfix) with ESMTP id B4FB5BC84
	for <caml-list@yquem.inria.fr>; Thu, 24 Mar 2005 09:13:22 +0100 (CET)
Received: from kurims.kurims.kyoto-u.ac.jp (kurims.kurims.kyoto-u.ac.jp [130.54.16.1])
	by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id j2O8DKSk031932
	for <caml-list@yquem.inria.fr>; Thu, 24 Mar 2005 09:13:22 +0100
Received: from localhost (suiren [130.54.16.25])
	by kurims.kurims.kyoto-u.ac.jp (8.13.1/8.13.1) with ESMTP id j2O8DAAQ024220;
	Thu, 24 Mar 2005 17:13:10 +0900 (JST)
Date: Thu, 24 Mar 2005 17:13:22 +0900 (JST)
Message-Id: <20050324.171322.41200116.garrigue@math.nagoya-u.ac.jp>
To: farr@mit.edu
Cc: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Object Attribute Accessor Syntax Extension
From: Jacques Garrigue <garrigue@math.nagoya-u.ac.jp>
In-Reply-To: <eb565b700ace2c0c96303c31515066f4@mit.edu>
References: <eb565b700ace2c0c96303c31515066f4@mit.edu>
X-Mailer: Mew version 4.2 on Emacs 21.3 / Mule 5.0 (SAKAKI)
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Miltered: at nez-perce with ID 424276A0.001 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)!
X-Spam: no; 0.00; caml-list:01 accessor:01 syntax:01 accessor:01 datatypes:01 clos:01 sytax:01 val:01 mutable:01 val:01 grammar:01 modular:01 grammar:01 syntax:01 expr:01 
X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on yquem.inria.fr
X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled 
	version=3.0.2
X-Spam-Level: 

> I think it would be nice to have accessor functions defined 
> automatically for simple datatypes (sort of a simplified version of the 
> :accessor q properties of a data member in CLOS -- Ruby does something 
> like this with its :attr_accessor a,b,c notes in the class definiton, 
> too, and Python probably has something similar).  The sytax I was 
> thinking of using was:
> 
> class body (m : float) (qq : float array) (pp : float array) =
> object
>    val mutable accessor m = m
>    val reader q = qq
>    val reader p = pp
>    val writer f = Array.make (Array.length pp) 0.0
>    (* etc *)
> end

Looks nice. I actually wrote the same extension (with the same names)
experimentally in the yacc grammar last year. Having it in camlp4
would be more modular. 
Note that in a yacc grammar your syntax would require "reader" and
"writer" to be keywords, but it may be OK with camlp4.
It may also be nice to have another small extension, so that
        o#f <- expr
would be handled as
        o#set_f <- (expr)

Jacques Garrigue