Just a reminder that Perl had both dynamic and static scoping

scoping.pl

$x = 0;
sub f { return $x; }
sub g { my $x = 1; return f(); }
print g()."\n";


# the power of scoping compels you, change global $y!
$y = 0;
sub f1 { return $y; }
sub g1 { local $y = 1; return f1(); }
print g1()."\n";

# $ perl ./scoping.pl
# 0
# 1

You can even do this:

sub a {
  our $foo = "foo";
}

sub f {
  our $foo;
  print $foo . "\n";
}

a();
f();
# prints "foo"