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Re: Common interval literals



Vincent,

I tried not to deviate much from John's original text:

"If the bare interval constructor has a bare common value x, the decorated
constructor has a decorated common value x com . Otherwise, it has no common value."

My primary concern is the setbased flavor. I would like that the standard with this value
is accepted as soon as possible. The suggestion to forbid demotion in bare version of textToInterval(s)
influenced behavior of the setbased flavor.
I understood this change and I assisted to formulate it.

Now we try to clean flavor-independent specification
without influence to behavior of the setbased flavor.
I don't feel myself an expert in flavor-independent specifictions because
there is no practice with flavors other than setbased.
I ask you and John to find an agreement in cleaning the common constructors text 9.5.

  -Dima


----- Original Message -----
From: vincent@xxxxxxxxxx
To: stds-1788@xxxxxxxxxxxxxxxxx
Sent: Wednesday, March 11, 2015 3:33:44 AM GMT +04:00 Abu Dhabi / Muscat
Subject: Re: Common interval literals

On 2015-03-10 07:04:18 -0700, Dmitry Nadezhin wrote:
> > Page 31 lines 25-26, I don't understand "except for the decorated
> > textToInterval(s) constructor."
> 
> This means that the textToInterval(s) constructor is an exemption of
> the above rule.
> 
> Bare constructor textToInterval("[1,2]_com") has no value, but the
> decorated constructor textToInterval("[1,2]_com") has the common
> decorated value "[1,2]_com".
> 
> Have you a suggestion how to say it clearer ?

So, the whole requirement seems wrong. IMHO, one should allow other
exceptions. For instance, a flavor may define a constructor very
similar to textToInterval(s), thus with the same exception for the
decorated constructor.

I would remove the whole sentence "Otherwise, it has no common value,
except for the decorated textToInterval(s) constructor." Or do you see
a good reason to require such a restriction for most constructors here
in the general requirements of the main standard?

-- 
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)