RE: [sv-ac] call to vote on 1549

John,

I looked at this a little.

Mantis 1350 discusses ambiguities with respect to the use of $, but the
basic restrictions are stated at the beginning of 6.20.2.1:

"The value $ can be assigned to parameters of integer types. A parameter
to which $ is assigned shall only be used wherever $ can be specified as
a literal constant."

Assigning $ to a variable does not fit those criteria.
Nor does passing $ as an argument.
You mentioned passing $ "as actual argument expression to a typed formal
argument."
I do not see that it could be passed even to an untyped formal argument.

I doubt even that what is written in 16.7 meets those criteria:

"An actual argument can replace any of the following:
 ...
 - Upper delay range or repetition range if the actual argument is $"

Regards,
Shalom


> -----Original Message-----
> From: John Havlicek [mailto:john.havlicek@freescale.com] 
> Sent: Friday, August 17, 2007 2:32 PM
> To: Bresticker, Shalom
> Cc: Bustan, Doron; Yaniv.Fais@freescale.com; sv-ac@eda-stds.org
> Subject: Re: [sv-ac] call to vote on 1549
> 
> Hi Shalom:
> 
> Lisa and I had a discussion yesterday about the example in 
> the 1549 proposal.
> 
> I do not think the LRM as it stands now allows $ to be 
> assigned to a variable or passed as actual argument 
> expression to a typed formal argument.  Do you know otherwise?
> 
> The main conceptual issue that I see with allowing $ to be 
> assigned to a variable or passed as actual argument 
> expression to a typed formal argument is defining what value 
> it has in the space of possible values for the associated data type.
> 
> It doesn't seem quite right to me to say that if $ is 
> assigned to a shortint, for example, then the value is the 
> largest one that can be represented in an shortint.  On the 
> other hand, maybe this is a useful and sensible definition.  
> With definitions of this kind, the meaning of $ is dependent 
> on the data type into which it is assigned or to which it is 
> bound, but there is already precedent for that in the various 
> coercion rules.
> 
> I recommended that we avoid this problem altogether for now 
> and not allow $ to be assigned to a variable or passed as 
> actual argument expression to a typed formal argument.  I 
> recommended that Lisa change the example to pass $ to a 
> context formal argument.
> 
> J.H.
> 
> > X-Authentication-Warning: server.eda-stds.org: majordom set 
> sender to 
> > owner-sv-ac@eda.org using -f
> > X-ExtLoop1: 1
> > X-IronPort-AV: E=Sophos;i="4.19,269,1183359600"; 
> >    d="scan'208";a="118117813"
> > X-MIMEOLE: Produced By Microsoft Exchange V6.5
> > Content-class: urn:content-classes:message
> > Date: Thu, 16 Aug 2007 09:15:58 +0300
> > X-MS-Has-Attach: 
> > X-MS-TNEF-Correlator: 
> > Thread-Topic: [sv-ac] call to vote on 1549
> > Thread-Index: AcfeiQ52OKcMoqhRQC+dKxDIPbJwOwADZVDwABotlYAAMwPDUA==
> > From: "Bresticker, Shalom" <shalom.bresticker@intel.com>
> > Cc: <sv-ac@eda-stds.org>
> > X-OriginalArrivalTime: 16 Aug 2007 06:15:59.0713 (UTC) 
> > FILETIME=[EA184510:01C7DFCC]
> > X-eda.org-MailScanner: Found to be clean, Found to be clean
> > X-Spam-Status: No, No
> > X-MIME-Autoconverted: from quoted-printable to 8bit by 
> > server.eda-stds.org id l7G6GDdJ019035
> > Sender: owner-sv-ac@eda.org
> > X-eda.org-MailScanner-Information: Please contact the ISP for more 
> > information
> > X-eda.org-MailScanner-From: owner-sv-ac@server.eda.org
> > 
> > The LRM states in other places restrictions on the use of $. 
> > The question is whether the example fulfills those conditions.
> > 
> > The following quoted wording is a little unclear: 
> > 
> > > An actual argument can replace any of the following:
> > > - Identifier
> > > - Expression
> > > - Event control expression
> > > - Upper delay range or repetition range if the actual 
> argument is $
> > 
> > "can replace" seems a little problematic here.
> > An actual argument cannot really replace an expression. E.g., it 
> > cannot replace a+b. It can replace a formal argument which 
> is used as 
> > an expression, which is a little different.
> > 
> > And does this list cover all the possibilities, or is it 
> just intended 
> > to be examples?
> > 
> > And does the last item mean:
> > 1. If the actual argument is $, it can be used only in this 
> way? If it 
> > is not $, can it be used in this way?
> > 2. It can be used in this way only if it is $? If it is $, 
> can it be 
> > used in another way?

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.