gistfile1.pl

#!/usr/bin/perl
use strict;
use warnings;

my $foo = "hello\n";

$a = undef;
$b = undef;
EVIL:
$foo = $a if $a; 
eval "goto $b" if $b; 

sub speak { print $foo };

my $foo = "bye\n";
speak();
print $foo;

$a = "Blah!\n";
$b = "GOAWAY";
goto EVIL;

GOAWAY:

speak();

exit;

__END__

"my" variable $foo masks earlier declaration in same scope at temp.pl line 15.
hello
bye
Blah!