package Exporter::All;
sub import {
    my @packages = @_;
    shift @packages;
    @packages = (caller)[0] unless defined @packages;
    foreach my $orig (@_) {
        *{"${orig}::import"} = sub {
            my $pkg = (caller)[0];
            foreach (grep {!/^import|__ANON__|BEGIN|END$/}
                         keys %{"${orig}::"}) {
                if (defined *{"${pkg}::$_"}) {
                    warn "Warning: symbol $_ already defined in $pkg."
                }
                else {
                    *{"${pkg}::$_"} = *{"${orig}::$_"};
                }
            }
        }
    }
}

1;

##</code><code>##

package Foo::Bar::Baz;
use Exporter::All;
sub x {print 1};

# ...

package main;
use Foo::Bar::Baz;
x();

##</code><code>##

package Foo::Bar::Baz;
sub x {print 1};

# ...

package main;
use Exporter::All qw(Foo::Bar::Baz);
x();