# @words is the list of words (composed of letters and numbers only, no punctuation)
my($self) = @_;
foreach $r (@words)
{
	$r{lc $r} = 1;
}
@words = sort keys %r;

##</code><code>##

# @seen is (I think) a pseudo-hash of common words
@common = qw(a and at); # bigger in real life
@seen{@common} = ();
foreach $item (@words) {
	push(@only,$item) unless exists $seen{$item};
}
@words = @only;