From: maranget@yquem.inria.fr (Luc Maranget)
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 10:43:29 +0100 [thread overview]
Message-ID: <20080227094329.GC13254@yquem.inria.fr> (raw)
In-Reply-To: <1204103370.7718.18.camel@Blefuscu>
> Along the lines of this discussion on Obj.magic, I have a question
> about the semantics of the beast.
I have not followed the discussion, but here are a few clues
The semantics of Obj.magic is as follows:
1. Obj.magic does not exist. Don't use it.
2. Obj.magic is black magic, you can see it as the identity
(fun x -> x) with type 'a -> 'b.
As I see it, 2. steems from the uniform representation of values by OCaml.
A value is either a scalar, or a pointer, and this can be tested
dynamically (by looking at the low order bit) by
Obj.is_int/Obj.is_block.
--
Luc
next prev parent reply other threads:[~2008-02-27 9:43 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 ` Luc Maranget [this message]
[not found] ` <37B36607-9F22-4537-B4DB-1E04348E2B90@inria.fr>
2008-02-28 14:23 ` [Caml-list] " 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
2008-02-27 21:22 ` David Teller
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