errata/155: A.1.3, module_declaration ambiguous

From: Brad Pierce (Brad.Pierce@synopsys.com)
Date: Wed Oct 09 2002 - 17:02:47 PDT


Precedence: bulk

>Number: 155
>Category: errata
>Originator: "Brad Pierce" <Brad.Pierce@synopsys.com>
>Environment:
>Description:

In A.1.3, module_declaration is ambiguous.

The fix is to remove the [] from around
list_of_port_declarations in the second
option --

   [list_of_port_declarations]
        -->
    list_of_port_declarations

To see the ambiguity, consider a case
where there is neither a list_of_ports nor
a list_of_port_declarations and, moreover,
after the semicolon there are no
port_declarations. Then it's ambiguous whether
there's a {module_item} or a {non_port_module_item}
and which of the options was used to generate
the module_declaration.

The proposed fix does more than just remove ambiguity.
It also more accurately reflects the actual intent of
the {non_port_module_item} restriction, which should
be imposed only in the case when there is a
list_of_port_declarations. Otherwise, a full
{module_item} is allowed.

-- Brad
 



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