NAME

XML::Easy::Element - abstract form of XML element

SYNOPSIS

    use XML::Easy::Element;

    $element = XML::Easy::Element->new("a", { href => "#there" },
		$content);

    $type_name = $element->type_name;
    $attributes = $element->attributes;
    $href = $element->attribute("href");
    $content = $element->content_object;

DESCRIPTION

An object of this class represents an XML element, a node in the tree making up an XML document. This is in an abstract form, intended for general manipulation. It is completely isolated from the textual representation of XML, and holds only the meaningful content of the element. The data in an element object cannot be modified: different data requires the creation of a new object.

The properties of an XML element are of three kinds. Firstly, the element has exactly one type, which is referred to by a name. Secondly, the element has a set of zero or more attributes. Each attribute consists of a name, which is unique among the attributes of the element, and a value, which is a string of characters. Finally, the element has content, which is a sequence of zero or more characters and (recursively) elements, interspersed in any fashion.

The element type name and attribute names all follow the XML syntax for names. This allows the use of a wide set of Unicode characters, with some restrictions. Attribute values and character content can use almost all Unicode characters, with only a few characters (such as most of the ASCII control characters) prohibited by the specification from being directly represented in XML.

This class is not meant to be subclassed. XML elements are unextendable, dumb data. Element objects are better processed using the functions in XML::Easy::NodeBasics than using the methods of this class.

CONSTRUCTOR

XML::Easy::Element->new(TYPE_NAME, ATTRIBUTES, CONTENT)

Constructs and returns a new element object with the specified properties. TYPE_NAME must be a string. ATTRIBUTES must be a reference to a hash in the same form that is returned by the accessor method attributes (below). CONTENT must be a reference to either an XML::Easy::Content object or a twine array (see "Twine" in XML::Easy::NodeBasics). All are checked for validity, against the XML 1.0 specification, and the function dies if any are invalid.

METHODS

$element->type_name

Returns the element type name, as a string.

$element->attributes

Returns a reference to a hash encapsulating the element's attributes. In the hash, each key is an attribute name, and the corresponding value is the attribute's value as a string.

The returned hash must not be subsequently modified. If possible, it will be marked as read-only in order to prevent modification. As a side effect, the read-only-ness may make lookup of any non-existent attribute generate an exception rather than returning undef.

$element->attribute(NAME)

Looks up a specific attribute of the element. The supplied NAME must be a string containing a valid attribute name. If there is an attribute by that name then its value is returned, as a string. If there is no such attribute then undef is returned.

$element->content_object

Returns a reference to an XML::Easy::Content object encapsulating the element's content.

$element->content_twine

Returns a reference to a twine array (see "Twine" in XML::Easy::NodeBasics) listing the element's content.

The returned array must not be subsequently modified. If possible, it will be marked as read-only in order to prevent modification.

$element->content

Deprecated alias for the "content_twine" method.

SEE ALSO

XML::Easy::Content, XML::Easy::NodeBasics

AUTHOR

Andrew Main (Zefram) <zefram@fysh.org>

COPYRIGHT

Copyright (C) 2008, 2009 PhotoBox Ltd

Copyright (C) 2009, 2010, 2011, 2017 Andrew Main (Zefram) <zefram@fysh.org>

LICENSE

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