VHDL Issue Number:      0105
Classification:         Examples, Notes, and Appendices
Language Version:       VHDL-87
Summary:                The note illustrating the equivalent sequence of
                        declarations for a constrained array type definition is
                        in error.
Related Issues:         None.
Relevant LRM Sections:  3.2.1
Key Words and Phrases:  Constrained array types
Current Status:         Submitted
1076-1993 Disposition:  Superseded (ISAC Issues Outstanding)
Disposition Rationale:  N/A
Superseded By:          1015
-----------------------
Date Submitted:         1988/06/04
Author of Submission:   Paul Menchini
Author's Affiliation:   CAD Language Systems, Inc.
Author's Post Address:  P.O. Box 13036
                        Research Triangle Park, NC  27709-3036
Author's Phone Number:  (919) 361-1913
Author's Fax Number:    
Author's Net Address:   mench@clsi.com
-----------------------
Date Analyzed:          TBD
Author of Analysis:     TBD
Revision Number:        $Revision: 1.9 $
Date Last Revised:      $Date: 1995/07/26 18:57:38 $


Description of Problem
----------------------
The note at the end of Section 3.2.1, on Page 3-10, illustrating the sequence
of declarations equivalent to the constrained array type declaration shown in
the note is incorrect.  The relevant LRM text (on the bottom of Page 3-9)
reads:

        "A constrained array definition defines both an array type
         and a subtype of this type:

             *  The array type is an implicitly declared anonymous
                type; this type is defined by an (implicit)
                unconstrained array definition, in which the element
                subtype indication is that of the constrained array
                definition, and in which the type mark of each index
                subtype definition denotes the subtype defined by the
                corresponding discrete range.

             *  The array subtype is the subtype obtained by imposition
                of the index constraint on the array type."

This text defines two declarations, not the three shown in the note on Page
3-10.


Proposed Resolution
-------------------
Change the note to read:

        "The rules concerning constrained type declarations mean that
         a type declaration with a constrained array declaration such
         as

                type T is array (POSITIVE range MIN to MAX) of ELEMENT;

         is equivalent to the sequence of declarations

                type array_type is array (POSITIVE range <>) of ELEMENT;
                subtype T is array_type (MIN to MAX);

         where array_type is anonymous.  Consequently, T is the name of
         a subtype and all objects declared with this type mark are
         arrays that have the same index range.


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


VASG-ISAC Recommendation for IEEE Std 1076-1987
-----------------------------------------------
TBD


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