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SPROUT / HTML-DOM-0.012 / lib / HTML / DOM / Collection.pm 

            

              
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package HTML::DOM::Collection;
use strict;
use warnings;
use Scalar::Util 'weaken';
our $VERSION = '0.012';
# Internals: \[$nodelist, $tie]
# Field constants:
sub nodelist(){0}
sub tye(){1}
sub seen(){2}     # whether this key has been seen
sub position(){3} # current (array) position used by NEXTKEY
sub ids(){4}      # whether we are iterating through ids
#  Number 5 is taken by ::Options (inside Element/Form.pm).
{ no warnings 'misc';
  undef &nodelist; undef &tye; undef &seen; undef &position;
}
use overload fallback => 1,
'%{}' => sub {
        my $self = shift;
        $$$self[tye] or
                weaken(tie %{ $$$self[tye] }, __PACKAGE__, $self),
                $$$self[tye];
},
'@{}' => sub { ${+shift}->[nodelist] };
sub new {
        bless \[$_[1]], shift;
}
my %NameableElements = map +($_ => 1), qw/
        a area object param applet input select textarea button frame 
        iframe meta form img map
/;
sub namedItem {
        my($self, $name) = @_;
        my $list = $$self->[nodelist];
        my $named_elem; my $elem;
        for(0..$list->length - 1) {
                no warnings 'uninitialized';
                ($elem = $list->item($_))->id eq $name and return $elem;
                exists $NameableElements{$elem->tag} and
                        $elem->attr('name') eq $name and
                        $named_elem = $elem;
        }
        $named_elem ||()
}
# Delegated methosd
for (qw/length item/) {
        eval "sub $_ { \${+shift}->[" . nodelist . "]->$_(\@_) }"
}
sub TIEHASH { $_[1] }
sub FETCH     { $_[0]->namedItem($_[1]) }
sub EXISTS    { $_[0]->namedItem($_[1]) } # nodes are true, undef is false
sub FIRSTKEY {
        my $self = shift;
        (my $guts = $$self)->[seen] = {};
        my($id,$item);
        $guts->[ids] = 1;
        for (0..$self->length - 1) {
                defined($id = ($item = $self->item($_))->id)
                        and ++$guts->[seen]{$id}, $guts->[position] = $_,
                            return($id);
        }
        # If none of the items has an id...
        $guts->[ids] = 0;
        for (0..$self->length - 1) {
                defined($id = ($item = $self->item($_))->attr('name'))
                        and ++$guts->[seen]{$id}, $guts->[position] = $_,
                            return($id);
        }
        return; # empty list
}
sub NEXTKEY{
        my $self = shift;
        my $guts = $$self;
        my($id,$item);
        if($guts->[ids]) {
                for ($guts->[position]..$self->length - 1) {
                        defined($id = ($item = $self->item($_))->id)
                                and !$guts->[seen]{$id}++
                                and $guts->[position] = $_,
                                    return($id);
                }
        }
        # If we've exhausted all ids...
        $guts->[ids] = 0;
        for (0..$self->length - 1) {
                defined($id = ($item = $self->item($_))->attr('name'))
                        and !$guts->[seen]{$id}++
                        and $guts->[position] = $_,
                            return($id);
        }
        return;
}
sub SCALAR {
        defined FIRSTKEY @_;
}
sub DDS_freeze { my $self = shift; delete $$$self[tye]; $self }
1
__END__
=head1 NAME
HTML::DOM::Collection - A Perl implementation of the HTMLCollection interface
=head1 SYNOPSIS
  use HTML::DOM;
  $doc = HTML::DOM->new;
  $doc->write('<html> ..... </html>');
  $doc->close;
   
  $images = $doc->images; # returns an HTML::DOM::Collection
     
  $images->[0];    # first image
  $images->{logo}; # image named 'logo'
  $images->item(0);
  $images->namedItem('logo');
   
  $images->length; # same as scalar @$images
=head1 DESCRIPTION
This implements the HTMLCollection interface as described in the W3C's DOM 
standard. This class is actually just a wrapper around the NodeList
classes. In addition to the methods below, you can use a collection as a
hash and as an array (both read-only).
=head1 CONSTRUCTOR
Normally you would simply call a method that returns an HTML collection
(as in the L</SYNOPSIS>). But if you wall to call the constructor, here is
the syntax:
  $collection = HTML::DOM::Collection->new($nodelist)
$nodelist should be a node list object.
=head1 OBJECT METHODS
=over 4
=item $collection->length
Returns the number of items in the collection.
=item $collection->item($index)
Returns item number C<$index>, numbered from 0. Note that you call also use
C<< $collection->[$index] >> for short.
=item $collection->namedItem($name)
Returns the item named C<$name>. If an item with an ID of C<$name> exists,
that will be returned. Otherwise the first item whose C<name> attribute is
C<$name> will be returned. You can also write C<< $collection->{$name} >>.
=back
=head1 SEE ALSO
L<HTML::DOM>
L<HTML::DOM::NodeList>