From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <oandrieu@gmail.com>
X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on yquem.inria.fr
X-Spam-Level: 
X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled 
	version=3.1.3
Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83])
	by yquem.inria.fr (Postfix) with ESMTP id A3C7EBB84
	for <caml-list@yquem.inria.fr>; Thu,  9 Oct 2008 10:43:38 +0200 (CEST)
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: AjgEALhg7UhKfU4YgWdsb2JhbACTFz4BARYiA6NPhwYBAoNo
X-IronPort-AV: E=Sophos;i="4.33,382,1220220000"; 
   d="scan'208";a="15828873"
Received: from ey-out-2122.google.com ([74.125.78.24])
  by mail2-smtp-roc.national.inria.fr with ESMTP; 09 Oct 2008 10:43:38 +0200
Received: by ey-out-2122.google.com with SMTP id 6so1357034eyi.15
        for <caml-list@yquem.inria.fr>; Thu, 09 Oct 2008 01:43:37 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=gamma;
        h=domainkey-signature:received:received:message-id:date:from:sender
         :to:subject:cc:in-reply-to:mime-version:content-type
         :content-transfer-encoding:content-disposition:references
         :x-google-sender-auth;
        bh=3QvQ/li83So8I963ioXBJXd24Utjxj16KFHNzO5tZqQ=;
        b=jdPPRY9pPyiouYH+PG2QFNLEb7Gtt6DRuP3Rzucj/nb4EhNg090PT5DHXRlVghLrUF
         Ajk8ny3r5SUp4xtiK9TLkC7YVV0TJxrhSGSafPHH4ySsfRO+Nr0t/hU4+9g/ph2/1mQ+
         6BIrXgYjvBb+RlTtTEzBItHWYPTOPLeAtovrM=
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version
         :content-type:content-transfer-encoding:content-disposition
         :references:x-google-sender-auth;
        b=UIdZ8PQuOlBqOyJK+r6W/oho7LaeAYmCm+yejPfW1Qw7wpaY76EzBXkeXGo3Lv9BfQ
         /IPiP8JGiBQQLDLdxXGzg5u/hb4Z3DchIZLHbqd+RbgpN9bziyyL+ovJM6WJTkfGe99o
         9Lln3sSOiNEg4ksCu08YzQZwI9R9Qsque+g5c=
Received: by 10.210.117.1 with SMTP id p1mr11352479ebc.28.1223541817789;
        Thu, 09 Oct 2008 01:43:37 -0700 (PDT)
Received: by 10.210.43.16 with HTTP; Thu, 9 Oct 2008 01:43:37 -0700 (PDT)
Message-ID: <95513600810090143y137a17bcib8a4a7a25c06d6ca@mail.gmail.com>
Date: Thu, 9 Oct 2008 10:43:37 +0200
From: "Olivier Andrieu" <oandrieu@nerim.net>
Sender: oandrieu@gmail.com
To: "Conglun Yao" <yaoconglun@gmail.com>
Subject: Re: [Caml-list] conjunctive type in polymorphic variants
Cc: caml-list@yquem.inria.fr
In-Reply-To: <f7b50d2a0810082115v6a604241l598c828611614c77@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <f7b50d2a0810082115v6a604241l598c828611614c77@mail.gmail.com>
X-Google-Sender-Auth: aea30af5e9e52441
X-Spam: no; 0.00; andrieu:01 oandrieu:01 conjunctive:01 variants:01 toploop:01 ocaml:01 variants:01 ocaml:01 parser:01 polymorphic:01 polymorphic:01 wrote:01 caml-list:01 constructor:01 nerim:01 

Hi,

On Thu, Oct 9, 2008 at 06:15, Conglun Yao <yaoconglun@gmail.com> wrote:
> Sorry, I can't fully understand the source code, but it seems we can
> only define a polymorphic variant with only one additional type
> declaration, like
>               `A of int   or `A of (int * int)
>  rather than `A of int * int

That's correct.

> It looks wired, as we can directly define
> type t = [ `A of int * int | `B of string ]  in toploop or a *.ml file.

yes, that's because ocaml handle the "of int * int" a bit differently
in regular and
polymorphic variant declarations:
  - in the regular variant the * is a separator between constructor
arguments (thus two arguments)
  - polymorphic variants only have one argument, so int * int is
treated as a whole type expression and * is the "tupling" operator

So yes, this looks wired in the ocaml parser.

-- 
  Olivier