From: Patrick M Doane <patrick@watson.org>
To: Chris Hecker <checker@d6.com>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] variant with tuple arg in pattern match?
Date: Wed, 4 Apr 2001 15:49:35 -0400 (EDT) [thread overview]
Message-ID: <Pine.BSF.3.96.1010404153920.5769B-100000@fledge.watson.org> (raw)
In-Reply-To: <4.3.2.7.2.20010404123148.03366c90@shell16.ba.best.com>
Hi Chris,
This only becomes an issue when the data being associated with a
constructor would need to be boxed. Since an int doesn't require any
boxing, the type 'foo = Foo of int' will work exactly as expected.
Boxing/unboxing optimizations can be very subtle. The most important
example I can think of is computation with complex numbers. Is it better
for the the representation to be as a pair of floats in one structure or
as two separate floats? Different parts of a program may do better with
one representation instead of the other.
As far as I understand, the compiler could choose a representation for
variants and insert the necessary transformation code to hide the issue
from the programmer entirely. I haven't thought about the issue much so
there could be a real problem that I'm not seeing. From what I remember,
SML does not make this kind of syntactic distinction.
Patrick
On Wed, 4 Apr 2001, Chris Hecker wrote:
>
> >I would certainly like it if Caml could:
> > 1) Treat this entirely as an optimization issue and not make a syntactic
> >distinction.
>
> I agree. Is there a reason why it's done this way? I guess you need to
> be able to bind another name to the tuple independently, and for that to
> work you need it to be another block on the heap. Maybe it's not
> possible in general to do the right thing.
>
> But wait, why isn't this a problem even with normal non-tupled values?
>
> In other worlds, how does type foo = Foo of int work when I take a
> reference to the int? It has to know I'm refering to the int to GC
> correctly. Why is the tuple version any different?
>
> I'm confused.
>
> Chris
>
>
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next prev parent reply other threads:[~2001-04-04 19:49 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-04-04 11:04 Chris Hecker
2001-04-04 18:47 ` Alain Frisch
2001-04-04 19:18 ` Patrick M Doane
2001-04-04 19:36 ` Chris Hecker
2001-04-04 19:49 ` Daniel de Rauglaudre
2001-04-05 8:19 ` Christian RINDERKNECHT
2001-04-04 19:49 ` Patrick M Doane [this message]
2001-04-06 13:52 ` Xavier Leroy
2001-04-07 1:42 ` Patrick M Doane
2001-04-07 6:44 ` Daniel de Rauglaudre
2001-04-07 7:42 ` Fergus Henderson
2001-04-08 19:45 ` Pierre Weis
2001-04-08 20:37 ` Charles Martin
2001-04-08 23:57 ` Brian Rogoff
2001-04-09 0:22 ` Alain Frisch
2001-04-09 16:07 ` Pierre Weis
2001-04-10 8:23 ` Michel Mauny
2001-04-10 9:14 ` Xavier Leroy
2001-04-10 10:09 ` Michel Mauny
2001-04-10 10:44 ` reig
2001-04-10 11:32 ` Michel Mauny
2001-04-10 11:47 ` reig
2001-04-10 12:10 ` reig
2001-04-10 12:35 ` Michel Mauny
2001-04-10 12:49 ` Marcin 'Qrczak' Kowalczyk
2001-04-09 6:23 ` Mattias Waldau
2001-04-09 7:34 ` Daniel de Rauglaudre
2001-04-09 15:57 ` Pierre Weis
2001-04-10 9:07 ` Sven LUTHER
2001-04-09 8:20 ` Christian RINDERKNECHT
2001-04-10 2:54 ` Patrick M Doane
2001-04-10 19:04 ` John Max Skaller
2001-04-08 0:22 jgm
2001-04-10 12:17 Dave Berry
2001-04-10 13:12 ` Marcin 'Qrczak' Kowalczyk
2001-04-10 21:26 ` Bruce Hoult
2001-04-10 22:34 ` John Prevost
2001-04-10 13:51 ` Frank Atanassow
2001-04-10 17:25 Dave Berry
2001-04-10 23:16 ` Marcin 'Qrczak' Kowalczyk
2001-04-10 17:33 Dave Berry
2001-04-10 22:34 ` John Prevost
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