#
# This software is Copyright 2005 by Elsevier Inc.  You may use it
# under the terms of the license at http://perl.plover.com/hop/LICENSE.txt .
#



###
### extract_headers
###

## Chapter 1 section 7

@tagged_texts = walk_html($tree, sub { ['MAYBE', $_[0]] }, 
                                 \&promote_if_h1tag);

sub promote_if_h1tag {
  my $element = shift;
  if ($element->{_tag} eq 'h1') {
    return ['KEEPER', join '', map {$_->[1]} @_];
  } else {
    return @_;
  }
}
sub extract_headers {
  my $tree = shift;
  my @tagged_texts = walk_html($tree, sub { ['MAYBE', $_[0]] }, 
                                      \&promote_if_h1tag);
  my @keepers = grep { $_->[0] eq 'KEEPER' } @tagged_texts;
  my @keeper_text = map { $_->[1] } @keepers;
  my $header_text = join '', @keeper_text;
  return $header_text;
}