#!/bin/perl -w

# Using XML::DOM
# Authors: Ingo Macherius <macherius@gmd.de>
# modified by Michel Rodriguez <mirod@xmltwig.com>
# with input from the XML::DOM author Enno Derksen <enno@erols.com>
# This example uses features from the Perl implementation of the DOM,
# namely the fact that you can get an array from the getElementsByTagName
# method, as in @nodes = $doc->getElementsByTagName ("prod")

use strict;
use XML::DOM;

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

my @nodes = $doc->getElementsByTagName ("prod");

my $i=0;

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

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

sub rhs {
    my $text;
    foreach my $rhs (@_)
    {
     my @nodes = $rhs->getChildNodes();

     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;
        $string =~ s/\s+/ /g; $string=~ s{\s$}{}g;
        return $string;
}