From: phil.clayton@lineone.net
Subject: Re: Quantified expressions: no support for restriction predicates
Date: Sun, 29 Apr 2012 11:37:19 -0700 (PDT)
Date: 2012-04-29T11:37:19-07:00 [thread overview]
Message-ID: <9912125.1780.1335724639338.JavaMail.geo-discussion-forums@ynee1> (raw)
In-Reply-To: <wcc62cihby1.fsf@shell01.TheWorld.com>
On Sunday, April 29, 2012 3:03:50 PM UTC+1, Robert A Duff wrote:
> phil.c...@lineone.net writes:
>
> > Drat. I knew about the parentheses. (Personally, I would have liked
> > parentheses to be required only when there is a syntactic ambiguity.
> > I suppose that is so often, you may as well have them all the time.)
>
> Note that you don't need "extra" parentheses.
> You can say "F(for all ...)" instead of "F((for all ...))".
I also knew that but didn't choose my words very well :)
> > My thinking is that having a predicate to restrict the elements that
> > one is quantifying over (just like a subtype predicate restricts the
> > elements of a subtype) would avoid the need to work out the equivalent
> > logical expression, which differs depending on the quantifier - a
> > likely source of error. So, while more syntax would be needed, this
> > should actually simplify quantification concepts.
>
> Well, if you are willing to give a name to the subtype, you
> can put a Static_Predicate or Dynamic_Predicate aspect on it.
> Does that help?
Is that actually possible for a Dynamic_Predicate? Section 3.2.4 Subtype Predicates, para 27/3 says:
The discrete_subtype_definition of a loop_parameter_specification
shall not denote ... or any subtype to which Dynamic_Predicate
specifications apply.
Phil
next prev parent reply other threads:[~2012-04-29 18:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-27 0:29 Quantified expressions: no support for restriction predicates phil.clayton
2012-04-27 23:43 ` Randy Brukardt
2012-04-28 11:30 ` phil.clayton
2012-04-29 14:03 ` Robert A Duff
2012-04-29 18:37 ` phil.clayton [this message]
2012-04-29 19:35 ` Robert A Duff
2012-05-01 2:48 ` Randy Brukardt
2012-05-01 11:35 ` phil.clayton
2012-04-30 15:57 ` Adam Beneschan
2012-05-01 11:14 ` phil.clayton
replies disabled
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox