New IR 2120

Attached is IR 2120. Although this issue is currently pretty esoteric, 
when we extend protected types to classes we will
need some way to solve this kind of reference.

Chuck Swart

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VHDL Issue Number:        2120  

Language_Version          VHDL-2002
Classification            Language Modeling Enhancement or Deficiency
Summary                   How to access objects in higher level nested protected type
Relevant_LRM_Sections     3.5 Protected types
                          6.3 Selected names
Related_Issues            
Key_Words_and_Phrases     
Authors_Name              James Unterburger
Authors_Phone_Number      503-685-0860
Authors_Fax_Number        
Authors_Email_Address     jamesu@model.com
Authors_Affiliation       Mentor Graphics
Authors_Address1          8005 SW Boeckman Rd
Authors_Address2          Wilsonville, OR 97070
Authors_Address3          

Current Status:           Submitted

Superseded By:

------------------------
Date Submitted:           22 August 2007
Date Analyzed:
Author of Analysis:
Revision Number:          0
Date Last Revised:

Description of Problem
----------------------

The rules for selected names do not allow a prefix that is a type
mark; when the prefix is an object of a protected type, the suffix
must be the name of a method of that protected type.
    
For nested protected types, in which an inner protected type body
appearing within an outer protected type body (after the corresponding
inner protected type declaration, of course) contains a declarative
item with the same identifier as a declarative item appearing in the
outer protected type body (declared prior to the appearance of the
inner protected type body), it is impossible to refer to the outer
protected type body's declarative item.
    
    type outer is protected
    end protected outer;
    
    type outer is protected body
       constant c : string :=    "Hello";
       type inner is protected
       end protected inner;
       type inner is protected body
          -- this should work, "c" is still string here
          constant c : natural := c'length;
          -- won't work because how to get outer's c?
          -- "c" now means the natural, but selected
          -- name is illegal
          constant c1 : string := outer.c & " inner";
       end protected body inner;
    end protected body outer;

Proposed Resolution
-------------------

Perhaps allow type mark prefix of selected name in this scenario.
There may be other uses too, as in

       record_type_mark.record_element_name'left

for example.

VASG-ISAC Analysis & Rationale
------------------------------
TBD

VASG-ISAC Recommendation for IEEE Std 1076-2002
-----------------------------------------------
TBD

VASG-ISAC Recommendation for Future Revisions
---------------------------------------------
TBD