Xpath

XPath parser in NPL

Title	XPath parser in NPL
Author(s)	WangTian?
Date	2007/12/28
File	script/ide/Xpath.lua

Description

XPath uses path expressions to select nodes in an XML document. The node is selected by following an xpath. An xpath consists of xpath expression and predicate(optional).

Sample Code

NPL.load("(gl)script/ide/XPath.lua");

local xmlDocIP = ParaXML.LuaXML_ParseFile("script/apps/Poke/IP.xml");
local xpath = "/mcml:mcml/mcml:packageList/mcml:package/";
local xpath = "//mcml:IPList/mcml:IP[@text = 'Level2_2']";
local xpath = "//mcml:IPList/mcml:IP[@version = 5]";
local xpath = "//mcml:IPList/mcml:IP[@version < 6]";
local xpath = "//mcml:IPList/mcml:IP[@version > 4]";
local xpath = "//mcml:IPList/mcml:IP[@version >= 5]";
local xpath = "//mcml:IPList/mcml:IP[@version <= 5]";

local xmlDocIP = ParaXML.LuaXML_ParseFile("character/v3/Pet/MGBB/mgbb.xml");
local xpath = "/mesh/shader/@index";
local xpath = "/mesh/boundingbox/@minx";
local xpath = "/mesh/submesh/@filename";
local xpath = "/mesh/submesh";

--
-- select nodes to an array table
--
local result = commonlib.XPath.selectNodes(xmlDocIP, xpath);

--
-- iterate on all nodes. 
--
for node in commonlib.XPath.eachNode(xmlDocIP, xpath) do
   commonlib.echo(node[1]);
end

-- debug: print the result table
NPL.load("(gl)script/kids/3DMapSystem_Misc.lua");
Map3DSystem.Misc.SaveTableToFile(result, "TestTable/LODxml.ini");

Member Functions

XPath.TraverseXMLTable1

traverse through the xml table to get nodes according to xpath expression / expression : Selects from the ROOT node

syntax

function XPath.TraverseXMLTable1(o, xpath, result)

parameters

o
xpath
result

XPath.TraverseXMLTable2

traverse through the xml table to get nodes according to xpath expression // expression : Selects nodes in the document from the current node that match the selection ANYWHERE in the document

syntax

function XPath.TraverseXMLTable2(o, xpath, currentPath, result)

parameters

o
xpath
currentPath
result

XPath.FilterResultPredicate

extract the sPredicate string into compareable format and filter the traverse result

syntax

function XPath.FilterResultPredicate(sPredicate, result)

parameters

sPredicate
result

XPath.FilterResultAttribute

filter the result according to sAttribute

syntax

function XPath.FilterResultAttribute(sAttribute, result)

parameters

sAttribute
result

XPath.selectNodes

Decs: XPath uses path expressions to select nodes in an XML document. The node is selected by following an xpath. An xpath consists of xpath expression and predicate(optional).

-- Supported path expressions are listed below:

-- nodename: Selects all child nodes of the named node / : Selects from the ROOT node // : Selects nodes in the document from the current node that match the selection ANYWHERE in the document @ : Selects attributes

-- Predicates are used to find a specific node or a node that contains a specific value. Predicates are always embedded in square brackets. Supported operators are listed below: < : number > : number <= : number >= : number = : number or string

-- operators: | : | operator in an XPath expression you can select several paths. (not implemented yet)

-- e.g: xpath: /mcml:mcml/mcml:packageList/mcml:package/*[mcml:AuthorName = 'ParaEngine']

e.g

xpath: /mcml:mcml/mcml:app/mcml:IPList/mcml:IP[@something < 23]

e.g

xpath: /mcml:mcml/mcml:app/mcml:IPList/mcml:IP[@something]

syntax

function XPath.selectNodes(xmlLuaTable, xpath)

parameters

xmlLuaTable
xpath

XPath.TraverseXMLTableNonRecursive1

traverse through the xml table to get nodes according to xpath expression / expression : Selects from the ROOT node

syntax

function XPath.TraverseXMLTableNonRecursive1(o, xpath, result)

parameters

o
xpath
result

XPath.eachNode

return an iterator of selected nodes in the XML document. see function XPath.selectNodes(xmlLuaTable, xpath) for parameter specification

syntax

function XPath.eachNode(xmlLuaTable, xpath)

parameters

xmlLuaTable
xpath

XPath.XMLDecodeString

Desc: Decode character references and standard entity references in the string (str).

• param str : the string to be decoded
• return __ : a new decoded string as the result.

syntax

function XPath.XMLDecodeString(str)

parameters

str	the string to be decoded

XPath.XMLEncodeString

Desc: Encode the following characters found in (str): & ' < > " and replace them with the standard entity references.

• param str : the string to be encoded
• return __ : an encoded string.

syntax

function XPath.XMLEncodeString(str)

parameters

str	the string to be encoded