#!/usr/bin/perl -w

# Using XML::DOM
# Authors:     Ingo Macherius <macherius@gmd.de>
#          and Michel Rodriguez <m.v.rodriguez@ieee.org>
# with input from the XML::DOM author Enno Derksen <enno@erols.com>

use strict;
use XML::DOM;

my $parser = XML::DOM::Parser->new;
my $doc = $parser->parsefile ("REC-xml-19980210.xml");

my $node_list = $doc->getElementsByTagName ("prod");
my @nodes;
my $len_node_list = $node_list->getLength();
for (my $j = 0; $j < $len_node_list; $j++) {
  push @nodes, $node_list->item($j); }

my $i=0;

foreach my $node(@nodes) {
    my $lhs = $node->getElementsByTagName("lhs")->item(0);

    my $rhs_list = $node->getElementsByTagName("rhs");
    my $len = $rhs_list->getLength();
    my @rhs;
    for (my $j = 0; $j < $len; $j++) {
      push @rhs, $rhs_list->item($j);
   }

    $i++;
    my $prod=   "[$i] "
              . $lhs->getFirstChild->getNodeValue()
              . " ::= "
              . rhs(@rhs);
    $prod= clean( $prod);
    print $prod, "\n";
}

sub rhs {
    my $text;
    foreach my $rhs (@_)
    {
     my $node_list = $rhs->getChildNodes();
     my $len_node_list = $node_list->getLength();
     my @nodes;
     for (my $j = 0; $j < $len_node_list; $j++) {
       push @nodes, $node_list->item($j); }

     foreach my $node (@nodes ) {
         if ($node->getNodeType() == XML::DOM::Node::ELEMENT_NODE()) {
           $text .= $node->getFirstChild()->getNodeValue()
             unless( $node->getFirstChild()->getNodeName eq '#comment');
     } else {
        $text .= $node->getNodeValue()
          unless( $node->getNodeName eq '#comment');
        }
      }
    }
    return $text;
}

sub clean { 
        my( $string)= @_;
	$string =~ s/\xc2\xa0/ /sg; # weird characters in the original document
        $string =~ s/\s+/ /g; $string=~ s{^\s}{}g; $string=~ s{\s$}{}g;
        return $string;
}