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Raku bindings to the libxml2 native library

[Raku LibXML Project] / [LibXML Module] / Item

class LibXML::Item

base class for namespaces and nodes


LibXML::Item is a base class for LibXML::Namespace and LibXML::Node based classes.

These are distinct classes in libxml2, but do share common methods: getNamespaceURI, localname(prefix), name(nodeName), type (nodeType), string-value, URI.

Also note that the LibXML::Node findnodes method can sometimes return either LibXML::Node or LibXML::Namespace items, e.g.:

use LibXML::Item;
for $elem.findnodes('namespace::*|attribute::*') -> LibXML::Item $_ {
   when LibXML::Namespace { say "namespace: " ~ .Str }
   when LibXML::Attr      { say "attribute: " ~ .Str }

Please see LibXML::Node and LibXML::Namespace.

Functions and Methods

sub ast-to-xml

sub ast-to-xml(
) returns LibXML::Item

Node constructor from data

This function can be useful as a succinct of building nodes from data. For example:

use LibXML::Element;
use LibXML::Item :&ast-to-xml;
my LibXML::Element $elem = ast-to-xml(
             "\n  ", # white-space
             '#comment' => ' Element Construction. ',
             "\n  ", :species[:name<Camel>, :humps["1 or 2"], :disposition["Cranky"]],
             "\n  ", :species[:name<Llama>, :humps["1 (sort of)"], :disposition["Aloof"]],
             "\n  ", :species[:name<Alpaca>, :humps["(see Llama)"], :disposition["Friendly"]],
say $elem;


  <!-- Element Construction. -->
  <species name="Camel"><humps>1 or 2</humps><disposition>Cranky</disposition></species>
  <species name="Llama"><humps>1 (sort of)</humps><disposition>Aloof</disposition></species>
  <species name="Alpaca"><humps>(see Llama)</humps><disposition>Friendly</disposition></species>

All DOM nodes have an .ast() method that can be used to output an intermediate dump of data. In the above example $elem.ast() would reproduce thw original data that was used to construct the element.

Possible terms that can be used are:

Term Description
name => [term, term, ...] Construct an element and its child items
name => str-val Construct an attribute
'xmlns:prefix' => str-val Construct a namespace
'text content' Construct text node
'?name' => str-val Construct a processing instruction
'#cdata' => str-val Construct a CData node
'#comment' => str-val Construct a comment node
[elem, elem, ..] Construct a document fragment
'#xml' => [root-elem] Construct an XML document
'#html' => [root-elem] Construct an HTML document
'&name' => [] Construct an entity reference
LibXML::Item Reuse an existing node or namespace

By convention native classes in the LibXML module are not directly exposed, but have a containing class that holds the object in a $.raw attribute and provides an API interface for it. The box method is used to stantiate a containing object, of an appropriate class. The containing object will in-turn reference-count or copy the object to ensure that the underlying raw object is not destroyed while it is still alive.

For example to box xmlElem raw object:

use LibXML::Raw;
use LibXML::Node;
use LibXML::Element;

my xmlElem $raw .= new: :name<Foo>;
say $raw.type; # 1 (element)
my LibXML::Element $elem .= box($raw);
$raw := Nil;
say $elem.Str; # <Foo/>

A containing object of the correct type (LibXML::Element) has been created for the native object.

method keep

method keep(
    LibXML::Raw::DOM::Node $
) returns LibXML::Item

Utility method that verifies that $raw is the same native struct as the current object.

2001-2007, Ltd.

2002-2006, Christian Glahn.

2006-2009, Petr Pajas.


This program is free software; you can redistribute it and/or modify it under the terms of the Artistic License 2.0