sub routine { 
   my($thingy, $tx) = @_; # $thingy is not used
   print "routine: $tx\n";
}

my $ref = \&routine; # take a reference to the sub
my $pkg = "main";
my $obj = bless do { \my $x };

# we could also say...
#   my $pkg = __PACKAGE__;
# ...to get any package we are in in compile time

##</code><code>##

# method calls

main->routine("foo");
main->$ref   ("foo");
$pkg->routine("foo");
$pkg->$ref   ("foo");
$obj->routine("foo");
$obj->$ref   ("foo");
# or even
(join'',map{chr}(109,97,105,110))->routine("foo");
__PACKAGE__->$ref("foo");
(bless \my $x)->$ref("foo");

# function calls

routine ('main', "foo");
$ref -> ('main', "foo");
routine ($pkg,   "foo");
$ref -> ($pkg,   "foo");
&$ref   ($pkg,   "foo");

routine ($obj,   "foo");
# etc.

##</code><code>##

my (undef, $thing) = @_;

##</code><code>##

shift @_; # drop first element of argument list
my ($thing) = @_;