use strict ; use warnings ;

my $lsub ;    # visible in the packages that follow

foo::z() ;    # Initialise $foo::foo_global
bar::z() ;    # Initialise $bar::bar_global
              # Show that $foo_global is visible in package bar::

print "After $lsub: \$bar\::bar_global eq '$bar::bar_global'\n" ;
              # Show that $lsub was set by bar::z()
              # Show that $bar::bar_global is accessable by its full name

my $b = foo::b() ;
              # Initialise foo::b()'s our $fred & return subroutine to access same 
print "After $lsub: &\$b() eq '", &$b(), "' eq \$foo\::fred eq '$foo::fred'\n" ;
              # Show that our $fred in foo::b() refers to $foo::fred
              # Show that $foo::fred is accessable by its full name

my $a = foo::a() ;
              # Initialse foo::c()'s our $bill & return subroutine to access same 
my $c = foo::c() ;
              # Initialse foo::c()'s our $bill & return subroutine to access same 

foo::c() ;    # Set foo::c()'s our $bill
print "After $lsub: &\$a() eq '", &$a(), "' eq \$foo\::bill eq '$foo::bill'\n" ; 
              # Show that foo::a()'s our $bill is the same as foo:c()'s
              # ... which is $foo::bill

foo::a() ;    # Set foo::a()'s our $bill
print "After $lsub: &\$c() eq '", &$c(), "' eq \$foo\::bill eq '$foo::bill'\n" ; 
              # Show that foo::c()'s our $bill is the same as foo:a()'s
              # ... which is $foo::bill


package foo ;

  our $foo_global ;

  sub a {
    $lsub = 'foo::a()' ;

    our $bill = 'foo::a -- \$bill' ;

    return sub { $bill ; } ;
  } ;

  sub b {
    $lsub = 'foo::b()' ;

    our $fred = 'foo::b -- \$fred' ;

### my $q = $bill ;     # Global symbol "$bill" requires explicit package name...
              # Remove '###' to show $bill is "out of scope" under use strict 'vars'

    return sub { $fred ; } ;
  } ;

  sub c {
    $lsub = 'foo::c()' ;

    our $bill = 'foo::c -- \$bill' ;

    my $q = $foo::fred ;
              # Show that we can access the global by its full name

    return sub { $bill ; } ;
  } ;

  sub z {
    $lsub = 'foo::z()' ;

    $foo_global = 'foo_global' ;
  } ;

package bar ;

  our $bar_global ;

  sub z {
    $lsub = 'bar::z()' ;

    $bar_global = 'bar_global' ;

    print "$lsub: \$foo_global eq '$foo_global'\n" ;
  } ;