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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