How come the following script:

#!/usr/bin/perl
use strict;
use warnings;

if (defined $ARGV[0]){
    open SOURCE, $ARGV[0] or die("$!");
    }
else{
    print "please tell me a file to covert..." and die;
}

print '<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article PUBLIC 
+"-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbo
+ok/xml/4.1.2/docbookx.dtd\">';
print "\n\n";

my $marker = 0;
my $isheader = 0;
my $isbreak = 0;
my $paranumber;
my $articlename;
my $line;
my $char;

$char = getc(SOURCE);
while ($char ne "\n"){
    track($char);
    if (defined $articlename){
        
        $articlename = "${articlename}$char";
    }
    else{
        $articlename = $char;
    }
    $char = getc(SOURCE);
}
$articlename = "${articlename}$char" if defined $articlename;
print "<article> <title>$articlename</title>";
print "<chapter>";
getc(SOURCE);
while($char = getc(SOURCE)){
    if($char eq "\n" and $marker == 1 and $isbreak == 0){
        track("found break");
        writeXMLelement($line,$isheader);
        $line = $char;
        $isbreak = 1;
        $isheader = 0;
        $paranumber++;
        
    }
    elsif($char eq "\n" and $marker == 2 and $isheader == 0){
        track("found header");
        $isbreak = 0;
        $isheader = 1;
    }
    elsif($char eq "\n"){
        $isbreak = 0;
        track("found newline");
        $marker++;
        $line = "$line " unless (!defined $line);
    }
    elsif($char =~ /[\w\s\d\.\,\:\;\"\'\?\!\0]/){
        $isbreak = 0;
        #track("found text");
        $marker = 0;
        if (defined $line){
        $line = "${line}$char";
        }
        else{
            $line = $char;
        }
    }

    else{
        $isbreak = 0;
        track("text not found");
        $marker++;
        $line = "$line " unless (!defined $line);
    }
    

}

sub writeXMLelement{
    my $element = $_[0];
    chomp $element;
    $element = reverse $element;
    chomp $element;
    $element = reverse $element;
    if ($_[1] == 0){
        print "\n<para>\n$element\n</para>\n";
    }
    elsif ($_[1] == 1){
        print "</chapter>";
        print "\n<chapter id=\"$element\">\n";
        print "<title>$element</title>\n";
    }
}

sub track{
    warn "\ntrack:$_[0] at $paranumber\n";
}

print "\n</chapter>";
print "\n</article>";
[download]

finishes when it reaches the following paragraph in the communist manifesto:

10. Free education for all children in public schools.

    Abolition of children's factory labour in its present form.

    Combination of education with industrial production, &c., &c.

this is not the only example of something which causes my script to baulk, and I'm stumped, anything to do with the reading process because I can only guess that my while loop isn't being satisfied