use NEXT;

no strict 'refs';
*{$package . '::function'} = sub {
  my $this = shift;
  # do something
  $this->NEXT::function(@_);
};
##</code><code>##

sub printcaller {
  my $caller = (caller(1))[3];
  print "$caller\n";
}

my $package = "testpackage";
*{$package.'::function'} = sub {
  printcaller();
};

testpackage::function();

##</code><code>##

sub printcaller {
  my $caller = (caller(1))[3];
  print "$caller\n";
}

my $package = 'testpackage';

eval qq{
  sub ${package}::function {
    printcaller();
  }
};

testpackage::function(); # Output: testpackage::function