# $Id: Builder.pm 4532 2004-05-11 05:15:40Z ezra $package XML::XPath::Builder;use strict;# to get array index constantsuse XML::XPath::Node;use XML::XPath::Node::Element;use XML::XPath::Node::Attribute;use XML::XPath::Node::Namespace;use XML::XPath::Node::Text;use XML::XPath::Node::PI;use XML::XPath::Node::Comment;use vars qw/$xmlns_ns $xml_ns/;$xmlns_ns = "http://www.w3.org/2000/xmlns/";$xml_ns = "http://www.w3.org/XML/1998/namespace";sub new {    my $class = shift;    my $self = ($#_ == 0) ? { %{ (shift) } } : { @_ };    bless $self, $class;}sub start_document {    my $self = shift;    $self->{IdNames} = {};    $self->{InScopeNamespaceStack} = [ {             '_Default' => undef,            'xmlns' => $xmlns_ns,            'xml' => $xml_ns,        } ];        $self->{NodeStack} = [ ];        my $document = XML::XPath::Node::Element->new();    my $newns = XML::XPath::Node::Namespace->new('xml', $xml_ns);    $document->appendNamespace($newns);    $self->{current} = $self->{DOC_Node} = $document;}sub end_document {    my $self = shift;        return $self->{DOC_Node};}sub characters {    my $self = shift;    my $sarg = shift;    my $text = $sarg->{Data};        my $parent = $self->{current};        my $last = $parent->getLastChild;    if ($last && $last->isTextNode) {        # append to previous text node        $last->appendText($text);        return;    }        my $node = XML::XPath::Node::Text->new($text);    $parent->appendChild($node, 1);}sub start_element {    my $self = shift;    my $sarg = shift;    my $tag  = $sarg->{'Name'};    my $attr = $sarg->{'Attributes'};    push @{ $self->{InScopeNamespaceStack} },         { %{ $self->{InScopeNamespaceStack}[-1] } };    $self->_scan_namespaces(@_);        my ($prefix, $namespace) = $self->_namespace($tag);        my $node = XML::XPath::Node::Element->new($tag, $prefix);        foreach my $name (keys %$attr) {	my $value = $attr->{$name};        if ($name =~ /^xmlns(:(.*))?$/) {            # namespace node            my $prefix = $2 || '#default';#            warn "Creating NS node: $prefix = $value\n";            my $newns = XML::XPath::Node::Namespace->new($prefix, $value);            $node->appendNamespace($newns);        }        else {	    my ($prefix, $namespace) = $self->_namespace($name);            undef $namespace unless $prefix;            my $newattr = XML::XPath::Node::Attribute->new($name, $value, $prefix);            $node->appendAttribute($newattr, 1);            if (exists($self->{IdNames}{$tag}) && ($self->{IdNames}{$tag} eq $name)) {    #            warn "appending Id Element: $val for ", $node->getName, "\n";                $self->{DOC_Node}->appendIdElement($value, $node);            }        }    }            $self->{current}->appendChild($node, 1);    $self->{current} = $node;}sub end_element {    my $self = shift;    $self->{current} = $self->{current}->getParentNode;}sub processing_instruction {    my $self = shift;    my $pi = shift;    my $node = XML::XPath::Node::PI->new($pi->{Target}, $pi->{Data});    $self->{current}->appendChild($node, 1);}sub comment {    my $self = shift;    my $comment = shift;    my $node = XML::XPath::Node::Comment->new($comment->{Data});    $self->{current}->appendChild($node, 1);}sub _scan_namespaces {    my ($self, %attributes) = @_;    while (my ($attr_name, $value) = each %attributes) {	if ($attr_name eq 'xmlns') {	    $self->{InScopeNamespaceStack}[-1]{'_Default'} = $value;	} elsif ($attr_name =~ /^xmlns:(.*)$/) {	    my $prefix = $1;	    $self->{InScopeNamespaceStack}[-1]{$prefix} = $value;	}    }}sub _namespace {    my ($self, $name) = @_;    my ($prefix, $localname) = split(/:/, $name);    if (!defined($localname)) {	if ($prefix eq 'xmlns') {	    return '', undef;	} else {	    return '', $self->{InScopeNamespaceStack}[-1]{'_Default'};	}    } else {	return $prefix, $self->{InScopeNamespaceStack}[-1]{$prefix};    }}1;__END__=head1 NAMEXML::XPath::Builder - SAX handler for building an XPath tree=head1 SYNOPSIS use AnySAXParser; use XML::XPath::Builder; $builder = XML::XPath::Builder->new(); $parser = AnySAXParser->new( Handler => $builder ); $root_node = $parser->parse( Source => [SOURCE] );=head1 DESCRIPTIONC<XML::XPath::Builder> is a SAX handler for building an XML::XPathtree.C<XML::XPath::Builder> is used by creating a new instance ofC<XML::XPath::Builder> and providing it as the Handler for a SAXparser.  Calling `C<parse()>' on the SAX parser will return theroot node of the tree built from that parse.=head1 AUTHORKen MacLeod, <ken@bitsko.slc.ut.us>=head1 SEE ALSOperl(1), XML::XPath(3)PerlSAX.pod in libxml-perlExtensible Markup Language (XML) <http://www.w3c.org/XML>=cut