my @a="a".."c";
my @b=1..3;

print "@a\n";

our $alias;
*alias=\$a[2];
{
  local $a[1]; # otherwise $a[1] is undefined after the loop
  while ( $a[1] = <@b>) {
    $alias=$a[1]+1;
    print "@a\n";
  }
}

print "@a\n";
__END__
a b c
a 1 2
a 2 3
a 3 4
a b 4