VHDL Issue Number: 0057 Classification: Language Definition Problem Language Version: VHDL-87 Summary: Named associations when invoking implicit operators is undefined. Related Issues: Relevant LRM Sections: 4.3.3.2 Key Words and Phrases: Implicitly-declared operator, named association Current Status: ISAC-Approved 1076-1993 Disposition: Closed (All Issues Completely Addressed) Disposition rationale: No language changes needed Superseded By: N/A ----------------------- Date Submitted: 1989/02/10 Author of Submission: Doug Dunlop Author's Affiliation: Intermetrics, Inc. Author's Post Address: 4733 Bethesda Ave #415 Bethesda, MD 20814 Author's Phone Number: (301) 657-3775 Author's Fax Number: Author's Net Address: dunlop@inmet.inmet.com ----------------------- Date Analyzed: 1991/01/15 Author of Analysis: Doug Dunlop Revision Number: $Revision: 1.9 $ Date Last Revised: $Date: 1995/05/13 19:34:42 $ Description of Problem ---------------------- The names of the formal parameters for implicitly- declared operators such as "+", etc., are not defined in the LRM. In Ada, these are defined as LEFT, RIGHT, etc, and one can invoke these operators using named associations. Can one invoke an implicitly-declared operator using named associations in VHDL? Proposed Resolution ------------------- Named associations are illegal for the implicitly-declared operators. VASG-ISAC Analysis & Rationale ------------------------------ Since the names of the formal parameters for implicitly-declared operators are not defined by the language, the logical conclusion is that language does not allow the use of named associations when invoking such operators. The user-need for invoking an implicitly-declared operator using named associations is probably slight at best. The only real reasons for changing the language so that it specifies the names of formal parameters for implicitly-declared operators are (1) more consistency with Ada and (2) this would complete the definition of the "subprogram specification" for implicitly-declared operators. Neither of these seem compelling. VASG-ISAC Recommendation for IEEE Std 1076-1987 ----------------------------------------------- It is illegal to use named associations when invoking an implicitly-declared operator. VASG-ISAC Recommendation for Future Revisions --------------------------------------------- It is not clear that it is worthwhile changing the language to include specification of the formal-parameter names for the implicitly-declared operators.