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347 lines
11 KiB
Lua
347 lines
11 KiB
Lua
---
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-- Overview:
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-- =========
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-- Standard XML event handler(s) for XML parser module (xml.lua)
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--
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-- Features:
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-- =========
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-- printHandler - Generate XML event trace
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-- domHandler - Generate DOM-like node tree
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-- simpleTreeHandler - Generate 'simple' node tree
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--
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-- API:
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-- ====
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-- Must be called as handler function from xmlParser
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-- and implement XML event callbacks (see xmlParser.lua
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-- for callback API definition)
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--
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-- printHandler:
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-- -------------
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--
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-- printHandler prints event trace for debugging
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--
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-- domHandler:
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-- -----------
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--
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-- domHandler generates a DOM-like node tree structure with
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-- a single ROOT node parent - each node is a table comprising
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-- fields below.
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--
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-- node = { _name = <Element Name>,
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-- _type = ROOT|ELEMENT|TEXT|COMMENT|PI|DECL|DTD,
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-- _attr = { Node attributes - see callback API },
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-- _parent = <Parent Node>
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-- _children = { List of child nodes - ROOT/NODE only }
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-- }
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--
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-- The dom structure is capable of representing any valid XML document
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--
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-- simpleTreeHandler
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-- -----------------
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--
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-- simpleTreeHandler is a simplified handler which attempts
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-- to generate a more 'natural' table based structure which
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-- supports many common XML formats.
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--
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-- The XML tree structure is mapped directly into a recursive
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-- table structure with node names as keys and child elements
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-- as either a table of values or directly as a string value
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-- for text. Where there is only a single child element this
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-- is inserted as a named key - if there are multiple
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-- elements these are inserted as a vector (in some cases it
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-- may be preferable to always insert elements as a vector
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-- which can be specified on a per element basis in the
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-- options). Attributes are inserted as a child element with
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-- a key of '_attr'.
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--
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-- Only Tag/Text & CDATA elements are processed - all others
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-- are ignored.
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--
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-- This format has some limitations - primarily
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--
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-- * Mixed-Content behaves unpredictably - the relationship
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-- between text elements and embedded tags is lost and
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-- multiple levels of mixed content does not work
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-- * If a leaf element has both a text element and attributes
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-- then the text must be accessed through a vector (to
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-- provide a container for the attribute)
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--
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-- In general however this format is relatively useful.
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--
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-- It is much easier to understand by running some test
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-- data through 'textxml.lua -simpletree' than to read this)
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--
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-- Options
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-- =======
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-- simpleTreeHandler.options.noReduce = { <tag> = bool,.. }
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--
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-- - Nodes not to reduce children vector even if only
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-- one child
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--
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-- domHandler.options.(comment|pi|dtd|decl)Node = bool
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--
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-- - Include/exclude given node types
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--
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-- Usage
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-- =====
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-- Pased as delegate in xmlParser constructor and called
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-- as callback by xmlParser:parse(xml) method.
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--
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-- See textxml.lua for examples
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-- License:
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-- ========
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--
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-- This code is freely distributable under the terms of the Lua license
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-- (<a href="http://www.lua.org/copyright.html">http://www.lua.org/copyright.html</a>)
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--
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-- History
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-- =======
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-- $Id: handler.lua,v 1.1.1.1 2001/11/28 06:11:33 paulc Exp $
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--
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-- $Log: handler.lua,v $
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-- Revision 1.1.1.1 2001/11/28 06:11:33 paulc
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-- Initial Import
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--@author Paul Chakravarti (paulc@passtheaardvark.com)<p/>
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---Handler to generate a string prepresentation of a table
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--Convenience function for printHandler (Does not support recursive tables).
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--@param t Table to be parsed
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--@returns Returns a string representation of table
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local function showTable(t)
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local sep = ''
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local res = ''
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if type(t) ~= 'table' then
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return t
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end
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for k,v in pairs(t) do
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if type(v) == 'table' then
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v = showTable(v)
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end
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res = res .. sep .. string.format("%s=%s",k,v)
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sep = ','
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end
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res = '{'..res..'}'
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return res
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end
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---Handler to generate a simple event trace
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local printHandler = function()
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local obj = {}
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obj.starttag = function(self,t,a,s,e)
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io.write("Start : "..t.."\n")
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if a then
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for k,v in pairs(a) do
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io.write(string.format(" + %s='%s'\n",k,v))
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end
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end
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end
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obj.endtag = function(self,t,s,e)
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io.write("End : "..t.."\n")
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end
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obj.text = function(self,t,s,e)
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io.write("Text : "..t.."\n")
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end
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obj.cdata = function(self,t,s,e)
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io.write("CDATA : "..t.."\n")
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end
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obj.comment = function(self,t,s,e)
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io.write("Comment : "..t.."\n")
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end
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obj.dtd = function(self,t,a,s,e)
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io.write("DTD : "..t.."\n")
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if a then
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for k,v in pairs(a) do
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io.write(string.format(" + %s='%s'\n",k,v))
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end
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end
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end
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obj.pi = function(self,t,a,s,e)
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io.write("PI : "..t.."\n")
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if a then
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for k,v in pairs(a) do
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io. write(string.format(" + %s='%s'\n",k,v))
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end
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end
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end
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obj.decl = function(self,t,a,s,e)
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io.write("XML Decl : "..t.."\n")
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if a then
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for k,v in pairs(a) do
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io.write(string.format(" + %s='%s'\n",k,v))
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end
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end
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end
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return obj
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end
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--Obtém a primeira chave de uma tabela
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--@param Tabela de onde deverá ser obtido o primeiro elemento
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--@return Retorna a primeira chave da tabela
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local function getFirstKey(tb)
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if type(tb) == "table" then
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--O uso da função next não funciona para pegar o primeiro elemento. Trava aqui
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--k, v = next(tb)
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--return k
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for k, v in pairs(tb) do
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return k
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end
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return nil
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else
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return tb
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end
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end
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---Handler to generate a lua table from a XML content string
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local function simpleTreeHandler()
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local obj = {}
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obj.root = {}
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obj.stack = {obj.root;n=1}
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obj.options = {noreduce = {}}
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obj.reduce = function(self,node,key,parent)
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-- Recursively remove redundant vectors for nodes
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-- with single child elements
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for k,v in pairs(node) do
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if type(v) == 'table' then
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self:reduce(v,k,node)
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end
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end
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if #node == 1 and not self.options.noreduce[key] and
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node._attr == nil then
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parent[key] = node[1]
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else
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node.n = nil
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end
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end
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--@param t Table that represents a XML tag
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--@param a Attributes table (_attr)
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obj.starttag = function(self,t,a)
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local node = {}
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if self.parseAttributes == true then
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node._attr=a
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end
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local current = self.stack[#self.stack]
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if current[t] then
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table.insert(current[t],node)
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else
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current[t] = {node;n=1}
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end
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table.insert(self.stack,node)
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end
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--@param t Tag name
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obj.endtag = function(self,t,s)
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--Tabela que representa a tag atualmente sendo processada
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local current = self.stack[#self.stack]
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--Tabela que representa a tag na qual a tag
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--atual está contida.
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local prev = self.stack[#self.stack-1]
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if not prev[t] then
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error("XML Error - Unmatched Tag ["..s..":"..t.."]\n")
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end
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if prev == self.root then
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-- Once parsing complete recursively reduce tree
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self:reduce(prev,nil,nil)
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end
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local firstKey = getFirstKey(current)
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--Se a primeira chave da tabela que representa
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--a tag atual não possui nenhum elemento,
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--é porque não há nenhum valor associado à tag
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-- (como nos casos de tags automaticamente fechadas como <senha />).
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--Assim, atribui uma string vazia a mesma para
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--que seja retornado vazio no lugar da tag e não
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--uma tabela. Retornando uma string vazia
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--simplifica para as aplicações NCLua
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--para imprimir tal valor.
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if firstKey == nil then
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current[t] = ""
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prev[t] = ""
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end
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table.remove(self.stack)
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end
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obj.text = function(self,t)
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local current = self.stack[#self.stack]
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table.insert(current,t)
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end
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obj.cdata = obj.text
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return obj
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end
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--- domHandler
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local function domHandler()
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local obj = {}
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obj.options = {commentNode=1,piNode=1,dtdNode=1,declNode=1}
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obj.root = { _children = {n=0}, _type = "ROOT" }
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obj.current = obj.root
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obj.starttag = function(self,t,a)
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local node = { _type = 'ELEMENT',
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_name = t,
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_attr = a,
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_parent = self.current,
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_children = {n=0} }
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table.insert(self.current._children,node)
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self.current = node
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end
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obj.endtag = function(self,t,s)
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if t ~= self.current._name then
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error("XML Error - Unmatched Tag ["..s..":"..t.."]\n")
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end
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self.current = self.current._parent
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end
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obj.text = function(self,t)
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local node = { _type = "TEXT",
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_parent = self.current,
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_text = t }
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table.insert(self.current._children,node)
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end
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obj.comment = function(self,t)
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if self.options.commentNode then
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local node = { _type = "COMMENT",
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_parent = self.current,
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_text = t }
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table.insert(self.current._children,node)
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end
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end
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obj.pi = function(self,t,a)
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if self.options.piNode then
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local node = { _type = "PI",
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_name = t,
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_attr = a,
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_parent = self.current }
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table.insert(self.current._children,node)
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end
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end
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obj.decl = function(self,t,a)
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if self.options.declNode then
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local node = { _type = "DECL",
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_name = t,
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_attr = a,
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_parent = self.current }
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table.insert(self.current._children,node)
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end
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end
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obj.dtd = function(self,t,a)
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if self.options.dtdNode then
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local node = { _type = "DTD",
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_name = t,
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_attr = a,
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_parent = self.current }
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table.insert(self.current._children,node)
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end
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end
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obj.cdata = obj.text
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return obj
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end
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return { simpleTreeHandler = simpleTreeHandler }
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