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From: Basile STARYNKEVITCH <basile@starynkevitch.net>
To: mfmorss@aep.com
Cc: caml-list caml-list <caml-list@yquem.inria.fr>
Subject: Re: [Caml-list] different records, same field name?
Date: Mon, 03 Mar 2008 17:55:59 +0100	[thread overview]
Message-ID: <47CC2D9F.6050109@starynkevitch.net> (raw)
In-Reply-To: <OF27A2428D.CC65E3C9-ON85257401.005C4529-85257401.005CAA42@aep.com>

mfmorss@aep.com wrote:
> 
> In any case, is it possible to define and use different types of records, 
> which nevertheless share some field names?  I have had difficulty doing 
> this in the toplevel.

It is not possible, for a simple reason:

Suppose you have two record type tr1 & tr2 sharing a common field name f

   type tr1 = { f : int; f1 : string }

   type tr2 = { f2 : float;  f: int }

Then the compiler won't be able to infer the type of function ff 
retrieving this field f

   let ff x = x.f

So the requirement that each field name is different is the price to pay 
to have type inference.

Regards
-- 
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
8, rue de la Faiencerie, 92340 Bourg La Reine, France
*** opinions {are only mines, sont seulement les miennes} ***


  parent reply	other threads:[~2008-03-03 16:56 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-03 16:51 mfmorss
2008-03-03 16:53 ` [Caml-list] " Jon Harrop
2008-03-03 16:55 ` Basile STARYNKEVITCH [this message]
2008-03-03 19:32   ` Kuba Ober
2008-03-03 21:04     ` Michael Wohlwend
2008-03-03 22:29     ` Jon Harrop
2008-03-03 18:45 ` DooMeeR
2008-03-04  9:52   ` Berke Durak
2008-03-04 10:25     ` David Teller

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