Re^3: What does '::' mean in constructs '$::foo' and '@::foo'?

[ikegami]

No. Assuming the purpose is to "defeat" use strict;, it was made obsolete by use vars qw( @foo );.

perl -e'
   use strict;
   @foo = 123;
   print "ok\n";
'
Global symbol "@foo" requires explicit package name at -e line 3.
Execution of -e aborted due to compilation errors.

$ perl -e'
   use strict;
   use vars qw( @foo );
   @foo = 123;
   print "ok\n";
'
ok

But since strict was introduced in Perl 5.000 and vars was introduced in Perl 5.002, it's safe to say that was not the book's reason for using @::foo.

In fact, it's not obsolete. You still need to use fully qualified names to refer to variables in namespaces other than the current one.

use Data::Dumper qw( Dumper );
local $Data::Dumper::Useqq = 1;
local $Data::Dumper::Sortkeys = 1;
print(Dumper($data));