C:\>perl -MO=Deparse -e "$foo = 'bar'";
$foo = 'bar';
-e syntax OK

C:\>perl -MO=Deparse -e "$main::foo = 'bar'";
$foo = 'bar';
-e syntax OK

C:\>perl -MO=Deparse -e "$::foo = 'bar'";
$foo = 'bar';
-e syntax OK

##</code><code>##

C:\>perl -MO=Deparse -e "package Foo; my $foo = 'bar'";
package Foo;
my $foo = 'bar';
-e syntax OK

C:\>perl -MO=Deparse -e "package Foo; my $::foo = 'bar'";
"my" variable $::foo can't be in a package at -e line 1, near "my $::foo "
Can't use global $::foo in "my" at -e line 1, near "my $::foo "
-e had compilation errors.

C:\>perl -e "package Foo; $::foo = 'foo'; print $foo"   


C:\>perl -e "package Foo; $::foo = 'foo'; print $main::foo"
foo
C:\>