VHDL Issue Number:      1071
Classification:         Language Definition Problem
Language Version:       VHDL-93
Summary:                The bounds of array aggregates are ill-defined.
Related Issues:         0207
Relevant LRM Sections:  7.3.2.2
Key Words and Phrases:  Array aggregates, index bounds, static, direction
Current Status:         Submitted
1076-1993 Disposition:  N/A
Disposition Rationale:  N/A
Superseded By:          N/A
-----------------------
Date Submitted:         1991/03/18
Author of Submission:   Paul Menchini (edited by Bill Paulsen)
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:    N/A
Author's Net Address:   mench@clsi.com
-----------------------
Date Analyzed:          TBD
Author of Analysis:     TBD
Revision Number:        $Revision: 1.6 $
Date Last Revised:      $Date: 1995/05/15 21:26:37 $
 
 
Description of Problem
----------------------
(This IR supersedes IR 0207.)

Paragraph 4 of Section 7.3.2.2 (on page 7-11) attempts to define the index
bounds of array aggregates not including an OTHERS choice.  The paragraph was
taken from Ada and modified, when it was modified, it seems that some VHDL
issues were not taken into account:
 
    1.  VHDL has both ascending and descending ranges; Ada as only ascending
        ranges.
 
    2.  There is no clear specification of whether and under what circumstances
        the bounds are locally static, globally static, or neither.  Consider
        especially the phrase "... the direction of the index subtype of the
        aggregate is that of the corresponding constrained array subtype...."
 
In addition, the Ada community has reported a significant number of issues in
the corresponding paragraph from the Ada LRM--those that are relevant should be
adopted into VHDL.
 
 
Proposed Resolution
-------------------
Modify the paragraph so that it describes how to compute the bounds of an array
aggregate not having an OTHERS choice under all circumstances.
 
 
VASG-ISAC Analysis & Rationale
------------------------------
TBD
 
 
VASG-ISAC Recommendation for IEEE Std 1076-1993
-----------------------------------------------
TBD
 
 
VASG-ISAC Recommendation for Future Revisions
---------------------------------------------
TBD