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digitalmars.D.bugs - [Issue 11616] New: Introduce virtual keyword and remove virtual-by-default

reply d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=11616

           Summary: Introduce virtual keyword and remove
                    virtual-by-default
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: preapproved
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: yebblies gmail.com
        ReportedBy: yebblies gmail.com


--- Comment #0 from yebblies <yebblies gmail.com> 2013-11-27 23:27:49 EST ---
Thread with discussion and Walter-approval:

http://forum.dlang.org/thread/yzsqwejxqlnzryhrkfuq forum.dlang.org?page=28#post-koqkhc:244nn:241:40digitalmars.com

1. Add warning for not marking a virtual method with 'virtual'
2. Deprecate not marking a virtual method with 'virtual'
3. Make it an error to not mark virtual methods with 'virtual'

At this point, all methods are marked with either 'virtual', 'final',
'abstract', or 'override' or are implicitly final. (eg template methods,
constructors)

4. Do not require 'final' to mark a function as final. (optional)

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next sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=11616


Manu <turkeyman gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |turkeyman gmail.com


--- Comment #1 from Manu <turkeyman gmail.com> 2013-11-27 05:18:15 PST ---
(In reply to comment #0)
 Thread with discussion and Walter-approval:
 
 http://forum.dlang.org/thread/yzsqwejxqlnzryhrkfuq forum.dlang.org?page=28#post-koqkhc:244nn:241:40digitalmars.com
 
 1. Add warning for not marking a virtual method with 'virtual'
 2. Deprecate not marking a virtual method with 'virtual'
 3. Make it an error to not mark virtual methods with 'virtual'
 
 At this point, all methods are marked with either 'virtual', 'final',
 'abstract', or 'override' or are implicitly final. (eg template methods,
 constructors)
 
 4. Do not require 'final' to mark a function as final. (optional)

Since I already started writing this, I may as well paste it here: http://wiki.dlang.org/DIP51 It can be updated if details emerge. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Nov 27 2013
prev sibling next sibling parent d-bugmail puremagic.com writes:
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--- Comment #2 from yebblies <yebblies gmail.com> 2013-11-28 00:46:08 EST ---
(In reply to comment #1)
 (In reply to comment #0)
 Thread with discussion and Walter-approval:
 
 http://forum.dlang.org/thread/yzsqwejxqlnzryhrkfuq forum.dlang.org?page=28#post-koqkhc:244nn:241:40digitalmars.com
 
 1. Add warning for not marking a virtual method with 'virtual'
 2. Deprecate not marking a virtual method with 'virtual'
 3. Make it an error to not mark virtual methods with 'virtual'
 
 At this point, all methods are marked with either 'virtual', 'final',
 'abstract', or 'override' or are implicitly final. (eg template methods,
 constructors)
 
 4. Do not require 'final' to mark a function as final. (optional)

Since I already started writing this, I may as well paste it here: http://wiki.dlang.org/DIP51 It can be updated if details emerge.

I updated it. The warning goes on the introducing method, not on the overriding one. This forces all methods to be correctly annotated, even if there are no derived classes. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
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--- Comment #3 from Manu <turkeyman gmail.com> 2013-11-27 06:58:10 PST ---
(In reply to comment #2)
 (In reply to comment #1)
 (In reply to comment #0)
 Thread with discussion and Walter-approval:
 
 http://forum.dlang.org/thread/yzsqwejxqlnzryhrkfuq forum.dlang.org?page=28#post-koqkhc:244nn:241:40digitalmars.com
 
 1. Add warning for not marking a virtual method with 'virtual'
 2. Deprecate not marking a virtual method with 'virtual'
 3. Make it an error to not mark virtual methods with 'virtual'
 
 At this point, all methods are marked with either 'virtual', 'final',
 'abstract', or 'override' or are implicitly final. (eg template methods,
 constructors)
 
 4. Do not require 'final' to mark a function as final. (optional)

Since I already started writing this, I may as well paste it here: http://wiki.dlang.org/DIP51 It can be updated if details emerge.

I updated it. The warning goes on the introducing method, not on the overriding one. This forces all methods to be correctly annotated, even if there are no derived classes.

You mean to disallow an implicit state? So it's not final-by-default, rather, it MUST be explicitly specified? -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
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--- Comment #4 from yebblies <yebblies gmail.com> 2013-11-28 02:07:18 EST ---
(In reply to comment #3)
 
 You mean to disallow an implicit state? So it's not final-by-default, rather,
 it MUST be explicitly specified?

final-by-default comes last. The plan is to force the user to annotate everything, then relax the rules again. This way no functions move from virtual->non-virtual without user intervention. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
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--- Comment #5 from Manu <turkeyman gmail.com> 2013-11-27 07:29:23 PST ---
(In reply to comment #4)
 (In reply to comment #3)
 
 You mean to disallow an implicit state? So it's not final-by-default, rather,
 it MUST be explicitly specified?

final-by-default comes last. The plan is to force the user to annotate everything, then relax the rules again. This way no functions move from virtual->non-virtual without user intervention.

Hmmm, okay. I guess that's fair enough. It makes it explicit for a while then there's no ambiguity of intent. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
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--- Comment #6 from Andrej Mitrovic <andrej.mitrovich gmail.com> 2014-02-12
12:58:07 PST ---
*** Issue 7726 has been marked as a duplicate of this issue. ***

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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--- Comment #7 from github-bugzilla puremagic.com 2014-02-25 15:38:44 PST ---
Commits pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/b900262a9cbde7247a5eb0abc9de218500f7e229
Issue 11616 - Introduce virtual keyword

Introduce the virtual keyword

https://github.com/D-Programming-Language/dmd/commit/28acc4a364f751225b544b12c082dab037783d12
Merge pull request #2895 from yebblies/issue11616

Issue 11616 - Introduce virtual keyword

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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bearophile_hugs eml.cc changed:

           What    |Removed                     |Added
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                 CC|                            |bearophile_hugs eml.cc


--- Comment #8 from bearophile_hugs eml.cc 2014-02-26 04:26:41 PST ---
A possibly silly question, is this code OK (currently it compiles)?


class Foo {
    virtual final void bar() {}
}
void main() {}

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--- Comment #9 from yebblies <yebblies gmail.com> 2014-02-26 23:33:07 EST ---
(In reply to comment #8)
 A possibly silly question, is this code OK (currently it compiles)?
 
 
 class Foo {
     virtual final void bar() {}
 }
 void main() {}

An oversight, it should give you an error the same as ` safe system void fun();` does. Please file a bug for it. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
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--- Comment #10 from bearophile_hugs eml.cc 2014-02-26 04:54:07 PST ---
(In reply to comment #9)

 An oversight, it should give you an error the same as ` safe  system void
 fun();`  does.  Please file a bug for it.

Yet it seems C++11 allows it: http://en.wikipedia.org/wiki/C%2B%2B0x#Explicit_overrides_and_final http://stackoverflow.com/questions/6788338/final-virtual-functions-in-c0x http://stackoverflow.com/questions/11704406/whats-the-point-of-a-final-virtual-function -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
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--- Comment #11 from yebblies <yebblies gmail.com> 2014-02-27 00:10:00 EST ---
(In reply to comment #10)
 (In reply to comment #9)
 
 An oversight, it should give you an error the same as ` safe  system void
 fun();`  does.  Please file a bug for it.

Yet it seems C++11 allows it: http://en.wikipedia.org/wiki/C%2B%2B0x#Explicit_overrides_and_final http://stackoverflow.com/questions/6788338/final-virtual-functions-in-c0x http://stackoverflow.com/questions/11704406/whats-the-point-of-a-final-virtual-function

Interesting... Still, because we have attribute scopes/labels that would be harmful in D. eg virtual: final: void fun(); Here fun should be final, not both virtual and final. This should behave the same way as "virtual final". -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
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