=**************************************
    = Name: Look up a word from Merriam-Webs
    =     ter site
    = Description:A special-purpose simple s
    =     cript that looks up a word from Merriam-
    =     Webster site.
    This script only uses Socket and no other external modules or packages, and it 
    demonstrates the use of POST method to submit a FORM. However, the specific use 
    of this script is limited to talking to www.m-w.com, and the fact that many 
    parameters are hard-coded makes it dependent on the stability of that web site. 
    Nonetheless, since everything is explicitly written, it is very easy to manually
    change those hard-coded strings
    = By: Found on the World Wide Web
    =**************************************
    
    #!/usr/bin/perl -w
    use Socket;
    use strict;
    my $word = $ARGV[0] or die "Usage: mw word\n";
    my $host = "www.m-w.com";
    my $port = 80;
    my $socketaddr;
    my $content = "jump=$word"; # This seems to work with white space in word
    my $wholePage = "";
    my $form = "";
    my $buf = "";
    my @listvalue = ();
    my @option = ();
    my $selections = 0;
    my $count = 0;
    while ($content) {
    openSock();
    post ($content);
    $wholePage = "";
    while ( <SOCK> ) {
    	$wholePage .= $_;
    }
    close SOCK;
    $wholePage =~ /(<form .*<\/form>)/gs;
    $form = $1 or die "Can not find the word\n";
    # this is heavy duty kludge, geared toward www.m-w.com, needs maintenance
    # find out if the form has a selection of options
    $selections = 0;
    if ($form =~ s/^To view.*?GO TO.$//m) {
    	$selections = 1;
    	@option = ($form =~ /^<option.*>(.*)$/mg);
    	@listvalue = ($form =~ /name=list value="(.*)">/g);
    }
    # convert html into something more readable
    $form =~ s/<br>/\n/g;# change html linebreak to newline
    $form =~ s/<option.*?\n//mg;# delete the selection list, to be shown later
    $form =~ s/<[^>]*>//g; # delete all the other html tags
    $form =~ s/>/>/g;# make visible the greater-than sign
    $form =~ s/</</g;# make visible the less-than sign
    $form =~ s/&/&/g;# make visible the less-than sign
    $form =~ s/\n+/\n/g;# delete multiple newlines
    print $form;
    print "\n";
    # prompt the user for further actions: look up another word or stop here
    $content = "";
    if ($selections) {
    	print "Here are the related words:\n";
    	for (my $i=0;$i<@option;$i++){
    		print "$i: $option[$i]\n";
    	}
    	print "\nEnter a number to select from the list, or enter . to quit\n";
    	$buf = <STDIN>; # don't know how to use "read"
    	chomp $buf;
    	if ($buf eq '.') {
    		$content = "";
    	}
    	elsif ($buf !~ /\d/ or $buf >= @option) {
    		print "What did you just do?\n";
    		$content = "";
    	}
    	else{
    		$content = "hdwd=$word&book;=Dictionary&jump;=";
    		$content .= urlencode ($option[$buf]);
    		$content .= "&list;=";
    		$content .= urlencode ($listvalue[0]);
    	}
    } # end of if selections
    } # end of while content
    ###########
    # subroutine: open a socket at SOCK
    ###########
    sub openSock {
    $socketaddr= sockaddr_in $port, inet_aton $host or die "Bad hostname\n";
    socket SOCK, PF_INET, SOCK_STREAM, getprotobyname('tcp') or die "Bad socket\n";
    connect SOCK, $socketaddr or die "Bad connection\n";
    select((select(SOCK), $| = 1)[0]);
    }
    ###########
    # subroutine: urlencode a string
    ###########
    sub urlencode {
    my $ask = shift @_;
    my @a2 = unpack "C*", $ask;
    my $s2 = "";
    while (@a2) {
    $s2 .= sprintf "%%%X", shift @a2;
    }
    return $s2;
    }
    ###########
    # subroutine: send post request to target web site
    ###########
    sub post {
    my $content = shift @_;
    print SOCK "POST http://www.m-w.com/cgi-bin/dictionary HTTP/1.0\n";
    print SOCK "Content-type: application/x-www-form-urlencoded\n";
    my $contentLength = length $content;
    print SOCK "Content-length: $contentLength\n";
    print SOCK "\n";
    print SOCK "$content";
    }
    =head1 NAME
    Save this file to "mw", which stands for merriam-webster, then you can run it as
    "mw word" or "perl mw word"
    =head1 DESCRIPTION
    a simple web robot to look up a word from Merriam-Webster site using POST 
    method, and print the text response to STDOUT. 
    =head1 README
    A special-purpose simple script that looks up a word from Merriam-Webster site.
    This script only uses Socket and no other external modules or packages, and it 
    demonstrates the use of POST method to submit a FORM. However, the specific use 
    of this script is limited to talking to www.m-w.com, and the fact that many 
    parameters are hard-coded makes it dependent on the stability of that web site. 
    Nonetheless, since everything is explicitly written, it is very easy to manually
    change those hard-coded strings
    =head1 PREREQUISITES
    requires strict module and Socket module
    =head1 SCRIPT CATEGORIES
    Web
    =cut