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From: "Tom Primožič" <tom.primozic@gmail.com>
To: "David Teller" <David.Teller@univ-orleans.fr>
Cc: Caml <caml-list@yquem.inria.fr>
Subject: Re: [Caml-list] Safe Obj.magic container ?
Date: Wed, 27 Feb 2008 12:23:45 +0100	[thread overview]
Message-ID: <c1490a380802270323l10c3613ajaacfc30e862e62cb@mail.gmail.com> (raw)
In-Reply-To: <1204103370.7718.18.camel@Blefuscu>

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The following are my experience and guesses, nothing
scientific/official/thoroughly tested:

> 1. can I assume that this is always going to work if u is 'a.'a   ?


Well, there is no type 'a.'a. You can have:
type u = { everything: 'a . 'a }
but this presupposes that values of type u are blocks (heap-allocated).
Therefore, if you cast a boolean (true) to type u, and then try to access
the everything field of the "new" value, you will get a segfault.

3. assuming the answer to 1. is No, is there a type u or a simple
> manipulation which should work for any type t ? Or perhaps just for
> polymorphic variants ?
>

type u = int
this will work for any type. You can even do pointer manipulation with it
(adding and subtracting even numbers of bytes).

Sorry everybody.

 - Tom

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  parent reply	other threads:[~2008-02-27 11:23 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-27  9:09 David Teller
2008-02-27  9:43 ` [Caml-list] " Luc Maranget
     [not found]   ` <37B36607-9F22-4537-B4DB-1E04348E2B90@inria.fr>
2008-02-28 14:23     ` Damien Doligez
2008-02-28 15:29       ` David Teller
2008-02-28 16:24         ` Damien Doligez
2008-02-29  1:52         ` Jacques Garrigue
2008-02-29  8:18           ` David Teller
2008-02-28 19:20       ` Jake Donham
2008-02-28 23:19         ` Richard Jones
2008-02-27 11:23 ` Tom Primožič [this message]
2008-02-27 21:22   ` David Teller

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