Issue 18210: 'Explicit copy' function to clarify view copy semantics (vsiplxx-rtf)
Source:  (Mr. Brooks Moses, brooks.moses(at)dpdx.net)
Nature: Enhancement
Severity: Minor
Summary: The rules for when a copy constructor "View v(w);" will create a view v
that aliases the view w are somewhat esoteric and likely to lead to
confusion -- the result depends on details of the type of w, which do
not appear on this line and (with templates) may be in an entirely
separate section of the code.


It would be handy to have versions of this statement which are
predictable with regards to copy or alias, and which make the intent
explicit.  Unfortunately this is not possible with the alias case, but
we can at least resolve it for the copy case.


Thus, I propose we add a deep_copy() function (or a method on views)
which would allow us to write "View v(deep_copy(w));" -- with the result
that v has the same size as w, and the same values, but is guaranteed to
be a copy rather than an alias.


(Note that the "deep_copy" name is just a stand-in; there may be better
names for this functionality.)


Resolution: In the interest of closing the current RTF so that the solutions to resolved issues can be made publically available, this issue is deferred to the next RTF.
Disposition: Deferred
Revised Text: 
Actions taken:
October 23, 2012: received issue
Discussion: 

End of Annotations:=====
te: Tue, 23 Oct 2012 11:51:29 -0700
From: Brooks Moses <brooks_moses@mentor.com>
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:10.0.2) Gecko/20120216 Thunderbird/10.0.2
To: <issues@omg.org>
Subject: VSIPL++ issue (#14 from me)
X-OriginalArrivalTime: 23 Oct 2012 18:51:30.0130 (UTC) FILETIME=[69ED3B20:01CDB14F]


Name:            Brooks Moses
Employer:        Mentor Graphics
mailFrom:        brooks_moses@mentor.com
Terms_Agreement: I agree
Specification:   VSIPL++
Section:         8 [view]
FormalNumber:    ptc/2012-07-27
Version:         1.2 - FTF Beta 1
Doc_Year:        2012
Doc_Month:       August
Doc_Day:         10
Page:            47-
Title:           'Explicit copy' function to clarify view copy semantics
Nature:          Enhancement
Severity:        Minor
B1:              Report Issue


Description:


The rules for when a copy constructor "View v(w);" will create a view v
that aliases the view w are somewhat esoteric and likely to lead to
confusion -- the result depends on details of the type of w, which do
not appear on this line and (with templates) may be in an entirely
separate section of the code.


It would be handy to have versions of this statement which are
predictable with regards to copy or alias, and which make the intent
explicit.  Unfortunately this is not possible with the alias case, but
we can at least resolve it for the copy case.


Thus, I propose we add a deep_copy() function (or a method on views)
which would allow us to write "View v(deep_copy(w));" -- with the result
that v has the same size as w, and the same values, but is guaranteed to
be a copy rather than an alias.


(Note that the "deep_copy" name is just a stand-in; there may be better
names for this functionality.)

- Brooks