foo.pl 8 Foo:: $foo is 'foo'
foo.pl 11 Bar:: $foo is 'foo'
foo.pl 13 main:: $foo is 'bar'
foo.pl 14 main:: $Foo::foo is 'foo'
bar.pl 7 Bar:: $foo is ''
bar.pl 12 Foo:: $foo is 'foo'
bar.pl 15 Bar:: $foo is 'foo'
main.pl 8 main:: $foo is 'bar'