open (FILE, $file) or die ("Couldn't open $file: $!");
@HTML = <FILE>;

for (@HTML)
{
    s/<!-- fillin\((.+?)\) -->/&{$templateCall->{$1}}/eg;
}

splice (@HTML, 0, 0, @HEADERS);

# this is a subroutine called by the templateCall to add
# a header
sub add_header
{
    my $header = shift;

    unshift (@HEADERS, $header);
}