use strict;

for (1 ..2){
    # Both variables are lexically scoped to the block.
    our ($o);  # Belongs to 'main' package.
    my  ($m);  # Does not belong to a package.

    # The variables differ with respect to newness.
    $o ++;
    $m ++;
    print __PACKAGE__, " >> o=$o m=$m\n";  # $m is always 1.

    # The package has changed, but we still have direct,
    # unqualified access to both variables, because the
    # lexical scope has not changed.
    package Fubb;
    print __PACKAGE__, " >> o=$o m=$m\n";
}

# The our() and my() variables differ with respect to privacy.
# We can still access the variable declared with our(), provided
# that we fully qualify its name, but the variable declared
# with my() is unavailable.
print __PACKAGE__, " >> main::o=$main::o\n";  # 5
print __PACKAGE__, " >> main::m=$main::m\n";  # Undefined.

# Attempts to access the variables directly won't compile.
# print __PACKAGE__, " >> o=$o\n";
# print __PACKAGE__, " >> m=$m\n";

# Variables declared with use vars() are like those declared
# with our(): belong to a package; not private; and not new.
# However, their scoping is package-based rather than lexical.
for (1 .. 9){
    use vars qw($uv);
    $uv ++;
}

# Even though we are outside the lexical scope where the
# use vars() variable was declared, we have direct access
# because the package has not changed.
print __PACKAGE__, " >> uv=$uv\n";

# And we can access it from another package.
package Bubb;
print __PACKAGE__, " >> main::uv=$main::uv\n";