RE: [sv-ec] reference to outer scope name from nested class

Daniel,

 

I believe all your concerns have been clarified in the 2008 LRM as part
of our name resolution efforts. But using the 2005 LRM, a class is just
another data type, and we don't show every data type being declared in
every context. As far as I know, there are no restrictions on declaring
particular data types in any context; only context restrictions on
assigning and referencing certain types. 

 

Section 6.9 Type Compatibility says that the data types are local to
their scope, and that the hierarchical path to that scope uniquely
identifies that type. It has to be that way because parameterization. In
your example, possible different values for P in each instance need to
be represented in unique types for C.

 

You cannot hierarchically refer to a type, so it is not possible to
refer to a class type from outside a module, regardless of whether it is
instantiated or not.

 

See mantis 2109 for a list of name resolution issues.

 

Dave

 

 

________________________________

From: owner-sv-ec@server.eda.org [mailto:owner-sv-ec@server.eda.org] On
Behalf Of danielm
Sent: Friday, December 14, 2007 8:03 AM
To: sv-ec@server.eda.org
Subject: [sv-ec] reference to outer scope name from nested class

 

1. Problem with classes declaration  nested in modules

 

module sub;

    reg a;

    parameter P=1;

    class C;

        bit [P:0] p;

        function new ();

            $display("test>>>>>>>>>>>>",a);  //reference to outter scope
variable a;

        endfunction

    endclass

    

    C c=new;

endmodule

 

In the LRM (chapter 7. classses) there is no single example of nesting
classes inside modules/programs/interfaces and resolving issues like
above.

 

The main issues for above are:

    - how to deal with multi intantation of module sub - there will be
multi class declaration each with separate set of static variables? what
about parametrized p declaration in each instance?

    - what happen if we use a class from module which is not
instantiated in the project? is it possible

This should be clearly described in LRM.

 

 

2. Problem with classes declaration nested in classes:

 

 

    class C;

        int i;

        static int si;

        class CC;

                function new();

                    $display(i,,si);

                endfunction

        endclass

    endclass

    

    C:CC cc=new;

 

Should non-static properties and function declared in outer class be
visible in inner class? 

IMHO  in above only the static property 'si'  should be accesible (like
i C language) -  this should be clearly pointed out by LRM.

If we allow reference to 'i' what will be the value if C::i not exists?

 

 

 

Daniel Mlynek


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