phpman > perldoc > XML::XPath::XMLParser

NAME
    XML::XPath::XMLParser - The default XML parsing class that produces a node tree

SYNOPSIS
        my $parser = XML::XPath::XMLParser->new(
                    filename => $self->get_filename,
                    xml => $self->get_xml,
                    ioref => $self->get_ioref,
                    parser => $self->get_parser,
                );
        my $root_node = $parser->parse;

DESCRIPTION
    This module generates a node tree for use as the context node for XPath processing. It aims to
    be a quick parser, nothing fancy, and yet has to store more information than most parsers. To
    achieve this I've used array refs everywhere - no hashes. I don't have any performance figures
    for the speedups achieved, so I make no apologies for anyone not used to using arrays instead of
    hashes. I think they make good sense here where we know the attributes of each type of node.

Node Structure
    All nodes have the same first 2 entries in the array: node_parent and node_pos. The type of the
    node is determined using the ref() function. The node_parent always contains an entry for the
    parent of the current node - except for the root node which has undef in there. And node_pos is
    the position of this node in the array that it is in (think: $node ==
    $node->[node_parent]->[node_children]->[$node->[node_pos]] )

    Nodes are structured as follows:

  Root Node
    The root node is just an element node with no parent.

        [
          undef, # node_parent - check for undef to identify root node
          undef, # node_pos
          undef, # node_prefix
          [ ... ], # node_children (see below)
        ]

  Element Node
        [
          $parent, # node_parent
          <position in current array>, # node_pos
          'xxx', # node_prefix - namespace prefix on this element
          [ ... ], # node_children
          'yyy', # node_name - element tag name
          [ ... ], # node_attribs - attributes on this element
          [ ... ], # node_namespaces - namespaces currently in scope
        ]

  Attribute Node
        [
          $parent, # node_parent - the element node
          <position in current array>, # node_pos
          'xxx', # node_prefix - namespace prefix on this element
          'href', # node_key - attribute name
          'ftp://ftp.com/', # node_value - value in the node
        ]

  Namespace Nodes
    Each element has an associated set of namespace nodes that are currently in scope. Each
    namespace node stores a prefix and the expanded name (retrieved from the xmlns:prefix="..."
    attribute).

        [
          $parent,
          <pos>,
          'a', # node_prefix - the namespace as it was written as a prefix
          'http://my.namespace.com', # node_expanded - the expanded name.
        ]

  Text Nodes
        [
          $parent,
          <pos>,
          'This is some text' # node_text - the text in the node
        ]

  Comment Nodes
        [
          $parent,
          <pos>,
          'This is a comment' # node_comment
        ]

  Processing Instruction Nodes
        [
          $parent,
          <pos>,
          'target', # node_target
          'data', # node_data
        ]

Usage
    If you feel the need to use this module outside of XML::XPath (for example you might use this
    module directly so that you can cache parsed trees), you can follow the following API:

  new
    The new method takes either no parameters, or any of the following parameters:

            filename
            xml
            parser
            ioref

    This uses the familiar hash syntax, so an example might be:

        use XML::XPath::XMLParser;

        my $parser = XML::XPath::XMLParser->new(filename => 'example.xml');

    The parameters represent a filename, a string containing XML, an XML::Parser instance and an
    open filehandle ref respectively. You can also set or get all of these properties using the get_
    and set_ functions that have the same name as the property: e.g. get_filename, set_ioref, etc.

  parse
    The parse method generally takes no parameters, however you are free to pass either an open
    filehandle reference or an XML string if you so require. The return value is a tree that
    XML::XPath can use. The parse method will die if there is an error in your XML, so be sure to
    use perl's exception handling mechanism (eval{};) if you want to avoid this.

  parsefile
    The parsefile method is identical to parse() except it expects a single parameter that is a
    string naming a file to open and parse. Again it returns a tree and also dies if there are XML
    errors.

NOTICES
    This file is distributed as part of the XML::XPath module, and is copyright 2000 Fastnet
    Software Ltd. Please see the documentation for the module as a whole for licencing information.