VHDL Issue Number:      0222
Classification:         Language Definition Problem
Language Version:       VHDL-87
Summary:                User defined attribute on function name
Related Issues:
Relevant LRM Sections:
Key Words and Phrases:
Current Status:         Submitted
1076-1993 Disposition:  Superseded (ISAC Issues Outstanding)
Disposition Rationale:  N/A
Superseded By:          1043
-----------------------
Date Submitted:         1991/03/04
Author of Submission:   Laurence Groves
Author's Affiliation:   Synopsys Inc.
Author's Post Address:  1098 Alta Ave.
                        Mountain View, CA 94043
Author's Phone Number:  (415) 962-5426
Author's Fax Number:    
Author's Net Address:   larry@Synopsys.COM
-----------------------
Date Analyzed:          TBD
Author of Analysis:     TBD
Revision Number:        $Revision: 1.9 $
Date Last Revised:      $Date: 1995/07/26 23:54:29 $


Description of Problem
----------------------
Consider the following:

        package P is
           function f return BIT_VECTOR;
           attribute length : integer;
           attribute length of f : function is 5;  -- is this allowed?
        end P;

When f'length is later used in a signal or variable assignment statement, or
anywhere else f'length is used, should f be interpreted as a function call,
in which case it is "appropriate for an array object" and thus the 'length is
the predefined attribute.  Or should it be interpreted as the name of a
function entity, in which case the 'length is the user defined attribute.


Proposed Resolution
-------------------
Interpret f as a function call and therefore f'length is the length of
the bit_vector returned by f.

Additionally, it is illegal for the user to attribute an object with an
attribute whose name conflicts with a predefined attribute of that object.


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


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


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