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 "die"s 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 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.