NAME
    XML::LibXML::Overlay - Overlays for XML files

SYNOPSIS
      # target.xml:
      ####
      # <catalog>
      #   <book id="book0" delete="me">
      #     <author>Larry Wall</author>
      #     <author>Tom Christiansen</author>
      #     <author>Delete Me!</author>
      #     <title>Programming Perl: There's More Than One Way To Do It</title>
      #     <isbn>9780596000271</isbn>
      #   </book>
      #   <book id="book2">
      #     <author>Elliotte Rusty Harold</author>
      #     <author>W. Scott Means</author>
      #     <title>XML in a Nutshell: A Desktop Quick Reference</title>
      #     <isbn>9780596007645</isbn>
      #   </book>
      # </catalog>
      
  # overlay.xml
      ####
      # <overlay>
      #   <target xpath="/catalog/book[@id='book0']/author[text()='Delete Me!']">
      #     <action type="delete" />
      #   </target>
      #   <target xpath="/catalog/book[@id='book2']">
      #     <action type="insertBefore">
      #       <book id="book2">
      #         <author>Mark Jason Dominus</author>
      #           <title>Higher-Order Perl. Transforming Programs with Programs</title>
      #           <isbn>9781558607019</isbn>
      #       </book>
      #     </action>
      #   </target>
      # </overlay>
      
  use XML::LibXML;
      use XML::LibXML::Overlay;
      
  my $overlay = XML::LibXML::Overlay->load_xml(
        'location' => '/path/to/overlay.xml',
      );
      my $target = XML::LibXML->load_xml(
        'location' => '/path/to/target.xml',
      );
      
  $overlay->apply_to($target);
      
  # do whatever you want with $target

DESCRIPTION
    XML::LibXML::Overlay allowes to apply overlay files to XML files. This
    modul is a rewirte of XML::Overlay, but it uses plain XML::LibXML
    instead of the Class::XML thru XML::Parser stack.

DETAILS
    XML::LibXML::Overlay inherits from XML::LibXML. So you can use
    XML::LibXML::Overlay like XML::LibXML. The only difference is, that
    "load_xml" returns a XML::LibXML::Overlay::Document instead of a
    XML::LibXML::Document.

  Tags
    Following Tags can be used in a overlay document.

   overlay
    Specifies the root element, and contains any target element.

   target
    Selectes one or more nodes of the target document given by the
    <i>xpath</i> attribute. Target Elements contain any number of action
    elements.

   action
    The attributes <i>type</i> and <i>attribute</i> of action nodes specify
    a action which sould be applied to the target element.

  Action attributes
    Following attributes can be used to specify an action.

   appendChild
    Appends the content of the action element as child to the end of the
    target nodes.

   delete
    Deletes the target element.

   insertBefore
    Inserts the content of the action element as sibling before the target
    nodes.

   insertAfter
    Inserts the content of the action element as sibling after the target
    nodes.

   setAttribute
    Sets the value of the specified attribute to the content of the action
    node.

   removeAttribute
    Removes the specified attribute.

METHODS
  load_xml
    Can be used link "load_xml" in XML::LibXML, but returns a
    XML::LibXML::Overlay::Document instead of a XML::LibXML::Document.

SEE ALSO
    XML::LibXML, XML::Overlay

AUTHOR
    Alexander Keusch, "<kalex at cpan.org>"

LICENSE
    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.