#!/usr/bin/perl

use strict;
use File::Basename;
use XML::Twig;

binmode(STDOUT, ":utf8");

my ($inFile)=@ARGV;

unless (open ("INFILE", "<:utf8", "$inFile")){
	die "$inFile: No such file or directory.";
}

my $t= XML::Twig->new( twig_handlers => 
					   {   "identifier" => \&section,
						   "record" => sub { $_[0]->flush; }
					   },
                       );
$t->set_pretty_print("nice");
$t->set_keep_encoding;
$t->parsefile($inFile);

exit 0;

sub section { 
	my( $t, $elt)= @_;
	my $elt_txt = $elt->text;
	my $new_elt;

	if ($elt_txt =~ /^http:\/\/arxiv.org/) {
		$new_elt = XML::Twig::Elt->new( $elt->tag . ".url" => $elt_txt);
	} elsif ( $elt_txt =~ /^doi:/ ) {
		$new_elt = XML::Twig::Elt->new( $elt->tag . '.doi' => $elt_txt);
	}
	$elt->replace_with($new_elt) if $new_elt;
}