Am Dienstag, den 11.08.2020, 16:41 -0400 schrieb Aaron Ballman:
> On Tue, Aug 11, 2020 at 4:38 PM Uecker, Martin via Liaison
> <liaison_at_[hidden]> wrote:
> >
> >
> > BTW: Is
> >
> > if (x)
> > int y;
> >
> > intentionally allowed in C++? Is there a sensible use
> > case?
>
> Yes, that's well-formed C++ code. A possible use case would be for an
> RAII object which performs work in its constructor or destructor (so
> the declaration itself causes code to be executed).

I understand this. I was thinking more about a
high-level example where it would make sense to use
it in this way.

A file which is opened and immediately close again
also does not make too much sense.

But maybe there are better examples?

Best,
Martin


> ~Aaron
>
> >
> > Best,
> > Martin
> >
> > Am Dienstag, den 11.08.2020, 22:11 +0200 schrieb Martin Uecker:
> > >
> > > Am Dienstag, den 11.08.2020, 21:31 +0200 schrieb Bjarne Stroustrup:
> > > > What benefits was this supposed to give programmers?
> > >
> > > It actually saves me time when writing C, because currently
> > > have to recompile sometimes just to add a pointless
> > > null statements. It is one of the main annoyances
> > > when writing C.
> > >
> > > It is also difficult to explain to students
> > > why you can not place a label before a declaration or
> > > at the end of a block while it makes perfect sense
> > > to jump there.
> > >
> > > C++ allows placing labels in front of declarations,
> > > so the also improves compatibility.
> > >
> > > > Was the benefits worth the change to almost 50 years practice and
> > > > documentation worth it?
> > >
> > > There is hardly anything to change, as it is entirely
> > > backward compatible and simply removes an annoying
> > > corner case from the language.
> > >
> > > > Are the old corner cases worse than the new ones?
> > >
> > > In C, there a no corner case anymore. You can place a label
> > > everywhere you could place a statement.
> > >
> > >
> > > Best,
> > > Martin
> > >
> > >
> > > > On 8/11/2020 6:43 PM, Richard Smith via Liaison wrote:
> > > > > On Tue, 11 Aug 2020, 09:16 Uecker, Martin,
> > > > > <Martin.Uecker_at_med.uni-goettingen.de
> > > > > <mailto:Martin.Uecker_at_med.uni-goettingen.de>> wrote:
> > > > >
> > > > > Am Dienstag, den 11.08.2020, 09:04 -0700 schrieb Richard Smith:
> > > > > > On Mon, 10 Aug 2020, 23:37 Uecker, Martin via Liaison, <
> > > > > > liaison_at_lists.isocpp.org <mailto:liaison_at_lists.isocpp.org>> wrote:
> > > > > >
> > > > > > >
> > > > > > > Hi all,
> > > > > > >
> > > > > > > I recently proposed changes to the C grammar which got
> > > > > > > voted into C2X by WG14 (N2508, also see N2496).
> > > > > > >
> > > > > > > This allows placing of labels everywhere in a compound
> > > > > > > statement, even before declarations and at the end
> > > > > > > of a block, which was not possible in C so far.
> > > > > > >
> > > > > > > Example:
> > > > > > >
> > > > > > > {
> > > > > > > start:
> > > > > > > int i;
> > > > > > > mid:
> > > > > > > int j;
> > > > > > > end:
> > > > > > > }
> > > > > > >
> >
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