Re: [sv-ec] Abstract classes and virtual methods

I had the following comments on Dave's latest proposal for Mantis 1308.

1. Overriding a virtual method

   Page 1, 1st paragraph, 3rd sentence:

   From:
      "A virtual method shall override a method in all of its base (parent)
      classes, whereas a non-virtual method shall only override a method
      in that class and its descendants."
   To:
      "The implementation of a virtual method shall override that method in all
      of its base (parent) classes, whereas the implementation of a non-virtual
      method may only override that method in that class and not in any of its
      parent classes."

2. Typo

   Page 1, 2nd paragraph, next to last sentence:

   From:
      "... but the presence of a default much match"
   To:
      "... but the presence of a default must match"


3. Example on page 1

   From:
      class My_Packet extends Packet;
   To:
      class My_Packet extends BasePacket;

   From:   (there are 4 cases of this same typo)
      endfuncion
   To:
      endfunction

4. Optional 'virtual' keyword

   Page 2, first paragraph.

   "Once a method has been identified as virtual, it shall remain virtual in
   any subclass that overrides it. The virtual keyword may be used in later
   declarations, but is not required."

   This appears to be an enhancement. Not only that, I don't believe that we
   want to add this capability. It should be up to the user to determine if
   a method should be virtual or not.

Neil



Rich, Dave wrote On 02/04/06 00:49,:
> I have updated the proposal to incorporate the feedback from the email
> reflector. http://www.eda.org/svdb/bug_view_page.php?bug_id=0001308.  I
> have attached a version with markups from 1800 to this for your
> convenience. 
> 
> There seems to be two remaining issues that need consensus.
> 
> 1. What level of matching defaults is needed for virtual methods? The
> current proposal only requires the presence of a default to match for
> each argument, not their expressions. I think a matching expression is
> unnecessary and not very useful.
> 
> 2. The syntax for declaring a method without an implementation. The
> current proposal reuses the syntax for out-of-class body, which is what
> Vera does. Some have suggested that this might be visually ambiguous,
> but I think since you have to mark the class as 'virtual', it is
> unlikely that you will be providing out-of-class bodies at the same
> time.
> 
> I may not be able to make most of Monday's meeting, but I think #2 is
> very critical because a lot of class libraries are being written as this
> very moment. Let's try to reach consensus on this issue via e-mail ASAP.
> 
> Thanks,
> 
> Dave
> 
> David Rich
> Verification Technologist
> Design Verification & Test Division
> Mentor Graphics Corporation
> dave_rich@mentor.com
> Office:   408 487-7206
> Cell:     510 589-2625
> 

-- 
---------------------------------------------------------------------
Neil Korpusik                                     Tel: 408-720-4852
Senior Staff Engineer                             Fax: 408-720-4850
Frontend Technologies - ASICs & Processors (FTAP)
Sun Microsystems
email: neil.korpusik@sun.com
---------------------------------------------------------------------