RE: [sv-ec] forward typedefs

I don't see the need for any of these restrictions. The class must be
completed before the end of the scope, before any elaboration begins,
and there's no ambiguity with identifiers.

Dave

> -----Original Message-----
> From: owner-sv-ec@server.eda.org [mailto:owner-sv-ec@server.eda.org]
On
> Behalf Of Francoise Martinolle
> Sent: Thursday, November 20, 2008 6:48 PM
> To: Vreugdenhil, Gordon
> Cc: sv-ec@server.eda.org
> Subject: RE: [sv-ec] forward typedefs
> 
> 
> 
> 
> If we assume it is legal to do this, can we only use positional
> association for the parameter values?
> 
> typedef class c;
> 
>  typedef c#(1,1) c_1_1;
>  typedef c#(.q (1), .p(2)) c_2_1;      // is this legal
>  typedef c#(,1) c_0_1;                 // can you use default values
> 
>  class c #(parameter p = 0, q = 0);
>  endclass
> -----Original Message-----
> From: Gordon Vreugdenhil [mailto:gordonv@model.com]
> Sent: Thursday, November 20, 2008 7:39 PM
> To: Francoise Martinolle
> Cc: sv-ec@eda.org
> Subject: Re: [sv-ec] forward typedefs
> 
> 
> This was discussed at some point though I don't recall if it was
through
> the reflector buried in the wider discussion or just in a meeting.  It
> certainly wasn't specified in the LRM.
> 
> My recollection was that Mark and I agreed that it would be legal to
> have a forward specialization as in your example.
> I think that there was some disagreement as to whether the implicit
> default specialization using just the name should be allowed.
Example:
> 
>     typedef class c;
>     typedef c d;
>     class c #(parameter p = 0); endclass
> 
> I was somewhat opposed to considering this as legal although it is
more
> symmetric to allow it.  My argument against is mostly one of
readability
> in terms of intent for a forward type "c#()" used as a forward is more
> obvious as to intent.
> 
> Gord.
> 
> 
> Francoise Martinolle wrote:
> > Can you create a class specialization of a class for which we only
> > have a forward typedefs?
> >
> > Is this allowed?
> >
> >
> > typedef class c;
> >
> > typedef c#(1) c_1;
> >
> > class c #(parameter p = 0);
> > endclass
> >
> > In mantis 2211, we discussed the usage of :: for incomplete typedefs
> > and we speicifed the
> >
> > following text:
> >
> >
> > A forward typedef shall be considered incomplete prior to the final
> > type definition. While incomplete forward
> >
> > types, type parameters, and types defined by an interface based
> > typedef may resolve to class types, use
> >
> > of the class scope resolution operator (see 8.22) to select a type
> > with such a prefix shall be restricted to a
> >
> > typedef declaration. It shall be an error if the prefix does not
> > resolve to a class.
> >
> > Example:
> >
> > * *
> >
> > *typedef *C;
> >
> > C::T x; // illegal; C is an incomplete forward type
> >
> > typedef C::T c_t; // legal; reference to C::T is made by a typedef
> >
> > c_t y;
> >
> > * *
> >
> > *class *C;
> >
> > * *
> >
> > *typedef *int T;
> >
> > * *
> >
> > *endclass*
> >
> >
> > --
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> --
> --------------------------------------------------------------------
> Gordon Vreugdenhil                                503-685-0808
> Model Technology (Mentor Graphics)                gordonv@model.com
> 
> 
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