NAME

XML::Parser::Lite::Tree::XPath - XPath access to XML::Parser::Lite::Tree trees

SYNOPSIS

use XML::Parser::Lite::Tree;
use XML::Parser::Lite::Tree::XPath;

my $xpath = new XML::Parser::Lite::Tree::XPath($tree);

my @nodes = $xpath->select_nodes('/photoset/photos');

DESCRIPTION

This module offers limited XPath functionality for XML::Parser::Lite::Tree objects. For more information about XPath see http://www.zvon.org/xxl/XPathTutorial/General/examples.html

METHODS

new($tree)

Returns an XML::Parser::Lite::Tree::XPath object for the given tree.

set_tree($tree)

Sets the tree for the object.

select_nodes($xpath)

Returns an array of nodes for the given XPath.

AXES

The child axis is used by default. The following rules are equivilent:

/foo/bar
/foo/child::bar

The following axes are supported:

ancestor
ancestor-or-self
child
descendant
descendant-or-self
following
following-sibling
preceding
preceding-sibling
parent
self

But these axes are not supported:

attribute
namespace

FUNCTIONS

Only a handful of the XPath functions are implemented. If you need further functions, send the author a test case and he'll try and implement them.

The following functions are supported:

last()
not()
normalize-space()
count()
name()
starts-with()
contains()
position()
string-length()
floor()
ceiling()

But these functions are not currently supported:

id()
string()
concat()
substring_before()
substring_after()
substring()
translate()
boolean()
true()
false()
lang()
number()
sum()
round()
x_lower()
x_upper()
generate_id()

UNSUPPORTED FEATURES

In addition to the unsupported functions and axes, several XPath features are also unsupported.

* attribute fetching
* relative paths

CAVEATS

Sub-rules are evaluated in a boolean context, except in the case where a subrule is a simple integer (e.g. //foo[3]). This has some odd side effects - the last() function returns a boolean specifying whether the element is the last in the set or not. To get the sequence number of the last element in a set (e.g. //foo[position() = last()]), use the last-id() function instead. If you need to do some sort of caclulation which would return a position (e.g. //foo[1+1]), then compare the value using the position() function to get the correct result (e.g. //foo[1+1 = position()]).

AUTHOR

Copyright (C) 2004, Cal Henderson, <cal@iamcal.com>

SEE ALSO

XML::Parser::Lite XML::Parser::Lite::Tree http://www.w3.org/TR/xpath