EntityRef

[Raku LibXML Project] / [LibXML Module] / EntityRef

class LibXML::EntityRef

Entity Reference nodes

use LibXML::Document;
use LibXML::Element;
use LibXML::EntityRef;
use LibXML::Dtd::Entity;
use LibXML::Enums;

my $string = q:to<END>;
<!DOCTYPE doc [
<!ENTITY foo "Foo ">
<!ENTITY bar " Bar">
]>
<doc>&foo;example</doc>
END

my LibXML::Document $doc .= parse: :$string;
my LibXML::Element $root = $doc.root;
my LibXML::EntityRef $foo-ref = $root.firstChild;
my LibXML::EntityRef $bar-ref = $doc.createEntityReference('bar');

# Reference to entity defined in DtD
say xmlEntityType($bar-ref.firstChild.entityType); # XML_INTERNAL_GENERAL_ENTITY

# Create reference to unknown entity
my LibXML::EntityRef $baz-ref =  $doc.createEntityReference('baz');
say $baz-ref.firstChild.defined; # False

# Create reference to predefined entity
my LibXML::EntityRef $gt-ref =  $doc.createEntityReference('gt');
say xmlEntityType($gt-ref.firstChild.entityType); # XML_INTERNAL_PREDEFINED_ENTITY

$root.appendChild: $bar-ref;
$root.appendChild: $baz-ref;
$root.appendChild: $gt-ref;

note $root.Str; # <doc>&foo;example&bar;&baz;&gt;</doc>

Description

LibXML::EntityRef objects represent entity references in a document. These may be either a predefined entity such as < or &gt, or a reference to an entity defined in an internal or external Dtd.

If the reference resolves to a predefined or Dtd entity, then it contains one child node of type LibXML::Dtd::Entity.

As a LibXML extension, entity references in attribute nodes may be examined and manipulated via the attribute's child nodes. For example:

use LibXML::Document;
use LibXML::Attr;
use LibXML::Enums;
my LibXML::Document $doc .= parse: :file<example/dtd.xml>;

my LibXML::Attr $att .= new: :name<att>, :value('xxx');
$att.addChild: $doc.createEntityReference('foo');
note $att.Str; # xxx test
note $att.childNodes[1].WHAT.raku; # LibXML::EntityRef;
$doc.root.setAttributeNode($att);

note $doc.root.Str; # <doc att="xxx&foo;">This is a valid document &foo; !</doc>