#/usr/bin/perl -w
use strict;

use LWP::RobotUA;
use HTML::SimpleLinkExtor;

use vars qw/$http_ua $link_extractor/;

sub crawl {
    my @queue = @_;
    my %visited;

    while(my $url = shift @queue) {
        next if $visited{$url};

        my $content = $http_ua->get($url)->content;
        # do useful things with $content
        # for example, save it into a file or index or whatever
        # i just print the url
        print qq{Downloaded: "$url"\n};

        push @queue,
		do { $link_extractor->parse($content); $link_extractor->a };
        $visited{$url} = 1;
    }
}

$http_ua = new LWP::RobotUA theusefulbot => 'bot@theusefulnet.com';
$link_extractor = new HTML::SimpleLinkExtor;

crawl(@ARGV);