From: skaller <skaller@users.sourceforge.net>
To: Brian Hurt <bhurt@spnz.org>
Cc: "Seth J. Fogarty" <sfogarty@gmail.com>, caml-list <caml-list@inria.fr>
Subject: Re: [Caml-list] References, compact bollean values (and other questions)
Date: Fri, 04 Nov 2005 13:39:43 +1100 [thread overview]
Message-ID: <1131071984.10871.50.camel@rosella> (raw)
In-Reply-To: <Pine.LNX.4.63.0511031805480.1006@localhost.localdomain>
On Thu, 2005-11-03 at 18:20 -0600, Brian Hurt wrote:
>
> On Thu, 3 Nov 2005, Seth J. Fogarty wrote:
>
> > First question: I notice references are implemented using mutable
> > records. Does this imply tuples of references are slower than mutable
> > records?
> > I.E.
> > type a = int ref * int ref * int ref
> > vs
> > type a = {mutable a : int; mutable b : int; mutable c : int}
>
> The mutable structure will almost certainly be less memory and faster.
> The tuple of structures will be a tuple of three pointers to three
> different mutable integers. The structure will simply be three integers,
> stored unboxed in the structure.
Yes but note it depends what you are doing.
A field is NOT a first class value. A reference is.
So if you use functional update to rebuild a record,
you are not tickling the write barrier -- true even
if a field is a reference.
So it depends what you are doing with these records, IMHO.
--
John Skaller <skaller at users dot sf dot net>
Felix, successor to C++: http://felix.sf.net
prev parent reply other threads:[~2005-11-04 2:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-03 23:34 Seth J. Fogarty
2005-11-04 0:20 ` [Caml-list] " Brian Hurt
2005-11-04 2:39 ` skaller [this message]
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