ISAC: Analysis of IR 2081

We'll discuss this at today's meeting.
Chuck Swart

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VHDL Issue Number:        2081

Language_Version          VHDL-2002
Classification            LRM Terminology, Grammar and Typographical Errors
Summary                   The term ancestor is used where parent is meant
Relevant_LRM_Sections     2.2, Note 6 on page 25.
                          8.1, on page 118.
Related_Issues            
Key_Words_and_Phrases     explicit ancestor, parent
Authors_Name              Peter Ashenden
Authors_Phone_Number      +61 414 709 106
Authors_Fax_Number        
Authors_Email_Address     peter@ashenden.com.au
Authors_Affiliation       Ashenden Designs
Authors_Address1          
Authors_Address2          
Authors_Address3          

Current Status:           Analyzed

Superseded By:

------------------------
Date Submitted:           24 January 2006
Date Analyzed:            02 February 2006
Author of Analysis:       Chuck Swart
Revision Number:          1
Date Last Revised:        02 February 2006

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

The term "ancestor" is used where the term "parent" should be
used. The term "explicit ancestor" is defined in 2.2 on page 24, and
refers to the signal or member of a signal that is a prefix of an
attribute name. The term "parent" is defined in 2.2 on page 23, and
refers to a process or subprogram that directly or indirectly calls a
given subprogram.
    
    In 2.2, Note 6 on page 25, the term "ancestor" is used to refer to
    a subprogram declared in a protected type declaration or body; the
    term "parent" is meant.
    
    In 8.1, on page 118, the term "ancestor" is used to refer to a
    subprogram whose body is declared within a protected type body;
    the term "parent" is meant.
    
    In both cases, the incorrect terminology was introduced in P1076a,
    probably as a result of misunderstanding of terminology by the
    language change authors. (I'm probably culpable, at least in
    part!)

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

Replace both occurrences of the term "ancestor" with "parent".

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

Part of the problem is the fact that the LRM definition of "parent"
does not match either the intuitive understanding of this word or the
graph-theoretic use of this word. From a graph-theoretic perspective
the word "ancestor" would be more accurate. The LRM could formally
define the word "ancestor" when applied to subprograms. However, such
a definition could cause confusion with the term "explicit ancestor"
which refers to signals.

Therefore, the ISAC believes that we should keep the current
definition of "parent" and make the changes suggested by the
submitter.


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

Interpret the LRM as if the recommendation for future revisions were
in effect.

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

Make the changes suggested by the submitter:

Change the word "ancestor" to "parent" in
a) 2.2 Note 6 on page 25, and
b) 8.1 on page 118.


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