On Apr 12, 2015 8:06 AM, "Shawn H Corey" <[email protected]> wrote:
>
> On Sat, 11 Apr 2015 21:20:22 -0700
> SSC_perl <[email protected]> wrote:
>
> > Could someone please explain the difference between:
> >
> > %{$self->{'DATA'}} = () }
>
> %{ $self->{'DATA'} } = ();
>
> >
> > and
> >
> > $self->{'DATA'} = {}
> >
> > I was told that they are equivalent, but they're not. One
> > works and the other doesn't, so they must be different. Here's the
> > context:
>
> No, they are not the exact same, as this snippet of code shows:
>
> my $self = { DATA => 1 };
> %{ $self->{'DATA'} } = ();
>
> If $self->{DATA} does not exist, then they are the same because Perl
> does autovivification. To get the first one to behave like the second,
> you should delete $self->{DATA}
>
> delete( $self->{DATA} );
> %{ $self->{'DATA'} } = ();
>
Right, you can change the example to make it different but the examples as
given are equivalent.
Here's another test for you :
my ($n, $m);
print "ok" if (ref(%{$n->{a}} = ()) eq ref($m->{a} = {}));
You could use something like Test::Deep to remove all doubt, but...
