Subject: Re: [sv-ac] cyclicity and ill-founded forms
From: John Havlicek (john.havlicek@motorola.com)
Date: Tue Feb 11 2003 - 23:08:37 PST
I had "syntactic cycles" in mind with my original question.
I have been thinking about definitions of elements like sequences,
where the syntactic cycles correspond to mutually recursive forms
that may be ill-founded. In any case, the mutually recursive
forms struck me as beyond the scope of what was intended.
J.H.
>
> Does this mean "semantic cycles" or "syntactic cycles". Simple cycles in
> the syntax are not necessarily going to ever occur semantically.
>
> Jay
>
> > -----Original Message-----
> > From: dudani@us04.synopsys.com [mailto:Surrendra.Dudani@synopsys.com]
> > Sent: Tuesday, February 11, 2003 11:45 AM
> > To: sv-ac@eda.org
> > Subject: Re: [sv-ac] cyclicity and ill-founded forms
> >
> >
> > John is correct. All "cyclic_definitions" are disallowed. LRM
> > needs to
> > state this restriction.
> > Surrendra
> > At 10:23 AM 2/10/2003 -0600, you wrote:
> > >Hi Adam:
> > >
> > >The example I gave has a cyclic syntactic dependency.
> > >s depends syntactically on t and x, while t depends syntactically
> > >on s and y. If you form a directed graph from the relation
> > >"depends syntactically on", that graph will have a cycle for these
> > >definitions.
> > >
> > >I think Surrendra meant to say that all _cyclic_ definitions are
> > >illegal.
> > >
> > >Best regards,
> > >
> > >John Havlicek
> > >
> > > > Good morning all;
> > > >
> > > > John wrote:
> > > >
> > > > I have not yet found any place in the LRM that mentions
> > > > acyclicity requirements for defined forms. Without
> > > > acyclicity, simple ill-founded forms are possible, e.g.
> > > >
> > > > seq s = (t;x);
> > > > seq t = (s;y);
> > > >
> > > > Is it intended that all cyclic syntactic dependencies be
> > > > disallowed?
> > > >
> > > > Surrendra wrote:
> > > >
> > > > All acyclic definitions are illegal. LRM should be updated to
> > > clearly state this
> > > > restriction.
> > > >
> > > >
> > > > In addition an example should be provided for those not
> > currently using
> > > terms
> > > > such as 'acyclicity'...
> > > >
> > > >
> > > > Adam Krolnik
> > > > Verification Mgr.
> > > > LSI Logic Corp.
> > > > Plano TX. 75074
> > > >
> > > >
> >
> >
> >
> > **********************************************
> > Surrendra A. Dudani
> > Synopsys, Inc.
> > 377 Simarano Drive
> > Suite 300
> > Marlboro, MA 01752
> >
> > Tel: 508-263-8072
> > Fax: 508-263-8123
> > email: dudani@synopsys.com
> > **********************************************
> >
> >
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