Received: (at 24102) by debbugs.gnu.org; 1 Mar 2017 08:51:40 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Wed Mar 01 03:51:40 2017 Received: from localhost ([127.0.0.1]:60956 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1cizz1-0007J7-Nv for submit <at> debbugs.gnu.org; Wed, 01 Mar 2017 03:51:39 -0500 Received: from pb-sasl1.pobox.com ([64.147.108.66]:55749 helo=sasl.smtp.pobox.com) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <wingo@HIDDEN>) id 1cizyz-0007J0-T4 for 24102 <at> debbugs.gnu.org; Wed, 01 Mar 2017 03:51:38 -0500 Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id 7DD8B48DBC; Wed, 1 Mar 2017 03:51:37 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=1FFTIkwuhYzkRbO8aRIG1ONhGT4=; b=lqzoHi B54X3OeOqcQ6jheajL2f9sLtrGWGPRxz/z08MiEqU8dg28Z+PuXJvGC6axYJCpdX j6daWFjT7rA2aTrMSEFJUgTh2O3yfvjyVczUx2SVCiY8s+68B+1D/hcYRMHrJHlA pKciN7/Zk+12pBKyQQVJqlk1SvH47RY//9PFU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; q=dns; s=sasl; b=CkBTlTXv1lKukGtIDNQzdQP7HxEQ92QS 7e3SLeT21yfXKfbkC4lMvxK/EauFgkdO+gx04r+aZC/SOEeq6pPZTqMmVDo8VaFw BQFfRws4NKF23r3FdaYBweGuh2AlUxWtSoLd/h1e9ipyZre6hek0+1SoHmovAK7K 06dpSxNcBK8= Received: from pb-sasl1.nyi.icgroup.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id 6757548DBA; Wed, 1 Mar 2017 03:51:37 -0500 (EST) Received: from clucks (unknown [109.190.228.233]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by pb-sasl1.pobox.com (Postfix) with ESMTPSA id 747EB48DB9; Wed, 1 Mar 2017 03:51:36 -0500 (EST) From: Andy Wingo <wingo@HIDDEN> To: Mark H Weaver <mhw@HIDDEN> Subject: Re: bug#24102: Use guile variable objects as SRFI-111 boxes. References: <N1O-ZjEQGzKD9q@HIDDEN> <87pop6uk9r.fsf@HIDDEN> <87wpixjoom.fsf@HIDDEN> Date: Wed, 01 Mar 2017 09:51:29 +0100 In-Reply-To: <87wpixjoom.fsf@HIDDEN> (Andy Wingo's message of "Wed, 31 Aug 2016 11:03:05 +0200") Message-ID: <87fuixjs6m.fsf@HIDDEN> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: 47366E08-FE5C-11E6-AF44-B667064AB293-02397024!pb-sasl1.pobox.com X-Spam-Score: 0.0 (/) X-Debbugs-Envelope-To: 24102 Cc: 24102 <at> debbugs.gnu.org, Glenn Michaels <gmichaels@HIDDEN> X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: 0.0 (/) On Wed 31 Aug 2016 11:03, Andy Wingo <wingo@HIDDEN> writes: > On Thu 18 Aug 2016 18:14, Mark H Weaver <mhw@HIDDEN> writes: > >> As I wrote above, the current guile compiler can already do this kind of >> type inference, although it does not currently do this for boxes. >> we can already anticipate having native code generation in the >> next couple of years, and we must keep boxes semantically simple so that >> our future compiler will be able to generate good code for this very >> important fundamental type. > > For what it's worth, I don't see the optimization argument as weighing > very heavily on this discussion. I would rather have fewer fundamental > data types rather than more, in the next two years or so. I see the > mid-term result here being that SRFI-111 boxes are much slower than > variables. > > The highest performance compilation tier we can imagine would include > adaptive optimization, and when it runs you can know that the variables > that a bit of code uses are bound or not. Also in that case we can > reasonably make any call to variable-unset! deoptimize any code that > uses variables, forcing it to reoptimize later. Since variable-unset! > is quite rare this is no big deal I think. Following up here :) So again I think the optimization argument is not so important; if that were the only consideration then IMO the balance of things would be that we should apply Glenn's patch. There is a semantic consideration as well -- box-ref on a box created by make-box should never throw an exception, and code that uses the SRFI-111 should be able to rely on this. We should probably not introduce a gratuitous incompatibility here. I propose to add a flag to variables indicating that certain variables may not be unset. We can also consider reversing this, in that only variables with the flag can be unset; my understanding is that the only user of variable-unset! is the Elisp language on variables that it creates, so that would be acceptable too. Andy
bug-guile@HIDDEN:bug#24102; Package guile.
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bug-guile@HIDDEN:bug#24102; Package guile.
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From: Mark H Weaver <mhw@HIDDEN>
To: "Glenn Michaels" <gmichaels@HIDDEN>
Subject: Re: bug#24102: Use guile variable objects as SRFI-111 boxes.
References: <N1O-ZjEQGzKD9q@HIDDEN>
Date: Thu, 18 Aug 2016 12:14:24 -0400
In-Reply-To: <N1O-ZjEQGzKD9q@HIDDEN> (Glenn Michaels's message of "Thu,
18 Aug 2016 09:07:26 -0400")
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"Glenn Michaels" <gmichaels@HIDDEN> writes:
> Sorry for the delayed response.
>
> Mark H Weaver <mhw@HIDDEN> writes:
>> > Moreover, SRFI-111 boxes and guile variable objects are clearly
>> > semantically the same thing.
>
>> Unfortunately, they are not quite the same thing. Unlike SRFI-111
>> boxes, Guile variables are a union type: they contain an arbitrary
>> Scheme value, *or* they may be "unbound". For such a simple data type,
>> this added complication is semantically quite significant.
>> As a result, some important properties of SRFI-111 boxes do not hold for
>> your proposed implementation. For example, in SRFI-111, (box? x)
>> implies that (box-ref x) will not raise an exception
>
> You're right. They aren't exactly the same, it would be more correct
> to say that boxes are equivalent to bound variables. Thus box? should
> be defined as:
>
> (define (box? o) (and (variable? o) (variable-bound? o)))
>
> That way, (box-ref o) is guaranteed to work whenever (box? o) holds.
The problem is, a variable that is bound can later become unbound. In
SRFI 111, if (box? x) is _ever_ true, then it will always remain true.
With your proposed definition above, that is not the case. Whether a
variable is bound is part of its mutable state.
> If a future guile compiler can implement boxes more efficiently in a
> different representation, there's nothing to stop you switching to
> that representation when the time comes.
If we adopted your suggestion, it's likely that some users would come to
rely on the fact that boxes are actually variables, with this extra
"feature" of supporting the "unbound" state, and then we wouldn't be
able to remove that feature without breaking existing code.
>> this fact can be exploited by a compiler to produce better native code for
>> 'box-ref' when the type of its argument is known to be a box. In such cases,
>> I guess 'box-ref' can be implemented as a single load instruction, whereas
>> 'variable-ref' will require a conditional branch.
>
> With respect to what you say about compiler optimizations: In order to
> implement a given call to unbox with a single load instruction, the
> compiler would have to prove that the argument is a box, i.e. that it
> satisfies the box? predicate.
Right, and the compiler that will be in Guile 2.2.x already has the
ability to perform this kind of type inference.
> You could also implement calls to variable-ref with a single
> load instruction in cases where the compiler can prove that the
> argument is a bound variable, i.e. that it satisfies
> (and (variable? o) (variable-bound? o)) -- precisely the definition of
> box? above.
It would very rarely be possible to prove that in practice, because the
"bound"-ness of a variable can change with time, and because in Scheme
it is very common to call procedures whose body is unknown at
compile-time, during which the bound-ness of the variable could change.
This is not a problem with SRFI-111 boxes, which will never change to
anything else.
> However, this discussing is academic insomuch as AFAICT the
> current guile compiler currently performs neither optimization.
As I wrote above, the current guile compiler can already do this kind of
type inference, although it does not currently do this for boxes.
However, we can already anticipate having native code generation in the
next couple of years, and we must keep boxes semantically simple so that
our future compiler will be able to generate good code for this very
important fundamental type.
Does that make sense?
Mark
bug-guile@HIDDEN:bug#24102; Package guile.
Full text available.Received: (at 24102) by debbugs.gnu.org; 18 Aug 2016 13:07:35 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Thu Aug 18 09:07:35 2016 Received: from localhost ([127.0.0.1]:60992 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1baN2k-0001i0-Px for submit <at> debbugs.gnu.org; Thu, 18 Aug 2016 09:07:34 -0400 Received: from orange.safe-mail.net ([212.29.227.81]:59706) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <gmichaels@HIDDEN>) id 1baN2i-0001hq-LH for 24102 <at> debbugs.gnu.org; Thu, 18 Aug 2016 09:07:33 -0400 Received: by orange.safe-mail.net with Safe-mail (Exim 4.84) (envelope-from <gmichaels@HIDDEN>) id 1baN2c-00087R-Nr; Thu, 18 Aug 2016 09:07:26 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=N1-0105; d=Safe-mail.net; b=r+IeCNqPeNwbxUMeFLwL5iqQbFNbjunvxChEvfn7kZGNyg57rLBvFidL7sUWSFfM Qx/8+U4a5o4yFLQqGoW331WmQX/cojeBnVw3KFirlOso3aN4kS269RBsQcfz3qOQ hxTS9ADtbxqlfHVdLUxUh8uCeHaAc+1xbt6FCvGzSuk=; Received: from pc ([94.23.150.95]) by Safe-mail.net with https Subject: Re: bug#24102: Use guile variable objects as SRFI-111 boxes. Date: Thu, 18 Aug 2016 09:07:26 -0400 From: "Glenn Michaels" <gmichaels@HIDDEN> To: mhw@HIDDEN X-SMType: Regular X-SMRef: N1O-ZjEQGzKD9q Message-Id: <N1O-ZjEQGzKD9q@HIDDEN> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-SMSignature: cdraO/6yuzI+eo8xaumcS353o4SAfanB0vXSGxTCe5KEpsDkLHCbJ0+H6XjdxR6Q +XBbQ0F2II/79ELFOGwQSKZ5Je2NswJAGM8G+FGtI9VtvFpO6c5YtKj1OlC818cm wCEGASj4KbAFaE+Gpyi+QaYy+mQ5VWEjgynVYdsdqps= X-Spam-Score: -1.2 (-) X-Debbugs-Envelope-To: 24102 Cc: wingo@HIDDEN, 24102 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -1.2 (-) Sorry for the delayed response. Mark H Weaver <mhw@HIDDEN> writes: > > Moreover, SRFI-111 boxes and guile variable objects are clearly > > semantically the same thing. > Unfortunately, they are not quite the same thing. Unlike SRFI-111 > boxes, Guile variables are a union type: they contain an arbitrary > Scheme value, *or* they may be "unbound". For such a simple data type, > this added complication is semantically quite significant. > As a result, some important properties of SRFI-111 boxes do not hold for > your proposed implementation. For example, in SRFI-111, (box? x) > implies that (box-ref x) will not raise an exception You're right. They aren't exactly the same, it would be more correct to say that boxes are equivalent to bound variables. Thus box? should be defined as: (define (box? o) (and (variable? o) (variable-bound? o))) That way, (box-ref o) is guaranteed to work whenever (box? o) holds. I'm suggesting that in current versions of Guile, implementing SRFI-111 boxes via variables is faster that the current implementation using records. With the definition of box? as above, it would be semantically correct. If a future guile compiler can implement boxes more efficiently in a different representation, there's nothing to stop you switching to that representation when the time comes. Making this simple change now doesn't prevent you from doing something different in future. I'm not suggesting that you should necessarily *guarantee* that boxes will always be implemented using variables. > this fact can be exploited by a compiler to produce better native code for > 'box-ref' when the type of its argument is known to be a box. In such cases, > I guess 'box-ref' can be implemented as a single load instruction, whereas > 'variable-ref' will require a conditional branch. With respect to what you say about compiler optimizations: In order to implement a given call to unbox with a single load instruction, the compiler would have to prove that the argument is a box, i.e. that it satisfies the box? predicate. You could also implement calls to variable-ref with a single load instruction in cases where the compiler can prove that the argument is a bound variable, i.e. that it satisfies (and (variable? o) (variable-bound? o)) -- precisely the definition of box? above. Therefore it seems to me that whether you can perform this optimization or not in a given case depends not so much on whether boxes and variables are distinct types, but on how much information the compiler can infer statically about each variable (in the general sense) reference at a given point the program. However, this discussing is academic insomuch as AFAICT the current guile compiler currently performs neither optimization.
bug-guile@HIDDEN:bug#24102; Package guile.
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From: Mark H Weaver <mhw@HIDDEN>
To: "Glenn Michaels" <gmichaels@HIDDEN>
Subject: Re: bug#24102: Use guile variable objects as SRFI-111 boxes.
References: <N1O-EYuO2QhvA6@HIDDEN> <87a8grygyc.fsf@HIDDEN>
Date: Fri, 05 Aug 2016 00:37:40 -0400
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Mark H Weaver <mhw@HIDDEN> writes:
> As a result, some important properties of SRFI-111 boxes do not hold for
> your proposed implementation. For example, in SRFI-111, (box? x)
> implies that (box-ref x) will not raise an exception, and this fact can
> be exploited by a compiler to produce better native code for 'box-ref'
> when the type of its argument is known to be a box. In such cases, I
> guess 'box-ref' can be implemented as a single load instruction, whereas
> 'variable-ref' will require a conditional branch.
s/box-ref/unbox/g
Mark
bug-guile@HIDDEN:bug#24102; Package guile.
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From: Mark H Weaver <mhw@HIDDEN>
To: "Glenn Michaels" <gmichaels@HIDDEN>
Subject: Re: bug#24102: Use guile variable objects as SRFI-111 boxes.
References: <N1O-EYuO2QhvA6@HIDDEN>
Date: Fri, 05 Aug 2016 00:31:39 -0400
In-Reply-To: <N1O-EYuO2QhvA6@HIDDEN> (Glenn Michaels's message of "Fri,
29 Jul 2016 05:21:53 -0400")
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Hi Glenn,
"Glenn Michaels" <gmichaels@HIDDEN> writes:
> Currently, guile's (srfi srfi-111) module ("mutable boxes") provides
> an implementation based on records with a single value field.
>
> Wouldn't it make more sense to re-export the functions make-variable,
> variable?, variable-ref and variable-set! from the guile core as box,
> box?, unbox and set-box! respectively?
>
> These functions have the same signatures and the same semantics as
> required by the SRFI-111 spec., and they appear to be significantly
> faster than the current record-based implementation.
>
> Moreover, SRFI-111 boxes and guile variable objects are clearly
> semantically the same thing.
Unfortunately, they are not quite the same thing. Unlike SRFI-111
boxes, Guile variables are a union type: they contain an arbitrary
Scheme value, *or* they may be "unbound". For such a simple data type,
this added complication is semantically quite significant.
As a result, some important properties of SRFI-111 boxes do not hold for
your proposed implementation. For example, in SRFI-111, (box? x)
implies that (box-ref x) will not raise an exception, and this fact can
be exploited by a compiler to produce better native code for 'box-ref'
when the type of its argument is known to be a box. In such cases, I
guess 'box-ref' can be implemented as a single load instruction, whereas
'variable-ref' will require a conditional branch.
Especially for such a simple and fundamental data type, I think it's
important to retain precisely the specified semantics, without *any*
additional complexity. For this reason, I am opposed to this change.
What do you think?
Regards,
Mark
bug-guile@HIDDEN:bug#24102; Package guile.
Full text available.Received: (at 24102) by debbugs.gnu.org; 4 Aug 2016 20:59:44 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Thu Aug 04 16:59:44 2016 Received: from localhost ([127.0.0.1]:55908 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1bVPk0-0003JV-Kl for submit <at> debbugs.gnu.org; Thu, 04 Aug 2016 16:59:44 -0400 Received: from pb-sasl1.pobox.com ([64.147.108.66]:57178 helo=sasl.smtp.pobox.com) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <wingo@HIDDEN>) id 1bVPjz-0003JO-B1 for 24102 <at> debbugs.gnu.org; Thu, 04 Aug 2016 16:59:43 -0400 Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id E23952EBBF; Thu, 4 Aug 2016 16:59:40 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=dzzGbEegOG34epbV39pcZKUBVQY=; b=W7tQww 5ZRoQK4UfGeVz1yMbV8VlqWsRfDWV1r0j5We6sr9t9B8433rhNyubEO501M3C+yo 6E+2u1B9uD+98nKZemO4CX2JSb/8sEDaRuDtE6OOpDdv6jstzasc7DXqB/b1WkRD oX0LSEvjPU7WVW97MeWwBCtYXf/mZbOUNZR3c= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; q=dns; s=sasl; b=NuKuIjxns9soW7UoEGLA2TvoPmG60/Fj dbEhhamrPDZnMPVeFyIQhzPETVRZc+Hs7wKsZOWSLm8HF8e93caQeCP0Imf/4rRt 2sHMl+/uZDOwiCYB97KwiTaNJHPjmd3psTALytzMJRQrfXEX/T7PC/QyDLE766dv 0aI5sdXUT9E= Received: from pb-sasl1.nyi.icgroup.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id D9B942EBBE; Thu, 4 Aug 2016 16:59:40 -0400 (EDT) Received: from clucks (unknown [88.160.190.192]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by pb-sasl1.pobox.com (Postfix) with ESMTPSA id 208BB2EBBC; Thu, 4 Aug 2016 16:59:40 -0400 (EDT) From: Andy Wingo <wingo@HIDDEN> To: "Glenn Michaels" <gmichaels@HIDDEN> Subject: Re: bug#24102: Use guile variable objects as SRFI-111 boxes. References: <N1O-EYuO2QhvA6@HIDDEN> <N1O-3bLcU31rOy@HIDDEN> Date: Thu, 04 Aug 2016 22:59:33 +0200 In-Reply-To: <N1O-3bLcU31rOy@HIDDEN> (Glenn Michaels's message of "Tue, 2 Aug 2016 06:25:56 -0400") Message-ID: <87twf0s11m.fsf@HIDDEN> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: 5C54FD60-5A86-11E6-A44A-C1836462E9F6-02397024!pb-sasl1.pobox.com X-Spam-Score: -1.2 (-) X-Debbugs-Envelope-To: 24102 Cc: 24102 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -1.2 (-) On Tue 02 Aug 2016 12:25, "Glenn Michaels" <gmichaels@HIDDEN> writes: > Trivial patch implementing this suggestion attached. > > --- a/module/srfi/srfi-111.scm > +++ b/module/srfi/srfi-111.scm > @@ -17,21 +17,9 @@ > ;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA > > (define-module (srfi srfi-111) > - #:use-module (srfi srfi-9) > - #:use-module (srfi srfi-9 gnu) > - #:export (box box? unbox set-box!)) > + #:re-export ((make-variable . box) > + (variable? . box?) > + (variable-ref . unbox) > + (variable-set! . set-box!))) > > (cond-expand-provide (current-module) '(srfi-111)) I like it. Let me check in with Mark and see if there's any reason to keep it like it is. Andy
bug-guile@HIDDEN:bug#24102; Package guile.
Full text available."Glenn Michaels" <gmichaels@HIDDEN>
to control <at> debbugs.gnu.org.
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Subject: Use guile variable objects as SRFI-111 boxes.
Date: Fri, 29 Jul 2016 05:21:53 -0400
From: "Glenn Michaels" <gmichaels@HIDDEN>
To: bug-guile@HIDDEN
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Currently, guile's (srfi srfi-111) module ("mutable boxes") provides
an implementation based on records with a single value field.
Wouldn't it make more sense to re-export the functions make-variable,
variable?, variable-ref and variable-set! from the guile core as box,
box?, unbox and set-box! respectively?
These functions have the same signatures and the same semantics as
required by the SRFI-111 spec., and they appear to be significantly
faster than the current record-based implementation.
Moreover, SRFI-111 boxes and guile variable objects are clearly
semantically the same thing. It's bad enough having two names for the
same thing, without having two implementations too.
Reference: http://srfi.schemers.org/srfi-111/srfi-111.html
"Glenn Michaels" <gmichaels@HIDDEN>:bug-guile@HIDDEN.
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