RE: [$ieee-1850] Illegal example in LRM: Is it illegal?

Hi Avigail,

Thanks for the clarification. I agree that sometimes it is more
efficient to implement forall differently. But there are other cases
also apart from this illegal example where it is not possible to
implement it in non-replicating way. So why single out this case and
make it illegal?

I think we should club this issue with Issue #36 raised by Ben Cohen
since it depends on what we want to write in LRM about non-replicating
implementation of forall.

Tej

> -----Original Message-----
> From: Avigail Orni [mailto:ORNIA@il.ibm.com]
> Sent: Monday, October 18, 2004 4:28 AM
> To: Singh, Tej
> Cc: ieee-1850@eda.org; owner-ieee-1850@eda.org
> Subject: Re: [$ieee-1850] Illegal example in LRM: Is it illegal?
>
>
> Hi Tej,
>
> I think that in this case the restriction is correct, but the
> text that states that "The parameter defined by a replicator
> is considered a static variable" should be changed.
>
> Your question underlines a general problem that exists in the
> "Replicated properties" section. The current text does not
> clarify two important
> points:
>
> (1) An implementation of "forall" might not actually
> replicate the property. It is sometimes more efficient to
> implement "forall" differently, and this should be allowed.
>
> (2) As a result of the previous point, the replicator
> parameter cannot really be considered to be a static
> variable. On the other hand, it's not really a dynamic
> variable either. I think the text should not try to
> categorize the replicator parameter, but should define its
> allowed behavior by listing the restrictions. These specify
> which behavior must be supported by all implementations, and
> which behavior should not be allowed.
>
> The specific restriction that you mention is important if we
> wish to allow non-replicating implementations.
>
> I hope that the LRM committee will succeed in rewriting this
> section so that it more clearly reflects the intent of the
> language definition.
>
> Regards,
> Avigail
>
> _______________________________________________________
> Avigail Orni
> Verification and Testing Solutions Group IBM Haifa Research Laboratory
> Phone: 972-4-829-6396 email: ornia@il.ibm.com
>
> owner-ieee-1850@eda.org wrote on 14/10/2004 21:03:22:
>
> > Hi All,
> >
> > One of the illegal example in 'Sec 6.2.3 Replicated properties' is
> >
> > forall j in {0:7}:
> > forall k in {0:j}:
> > f(j,k)
> >
> > I fail to understand why this example is illegal. Probably
> because a
> > replicator parameter is used in the Value range of the
> nested replicator.
> > But nowhere does the LRM say that this is illegal. Per LRM
> >
> > "If a Range is used to specify a Value Range, the Range shall be a
> > finite Range, each bound of the Range shall be statically
> computable,
> > and the left bound of the Range shall be less than or equal to the
> > right bound of the Range."
> >
> > A replicator parameter is static variable. Thus {0:j}
> satisfies the
> > restrictions on value range.
> >
> > Should this example be removed from the LRM?
> >
> > Regards
> > Tej
> >
>
>
Received on Mon Oct 18 10:35:12 2004