xml.lua

#!/usr/bin/env lua
--[[

xml.lua - XML parser for use with the Corona SDK.

version: 1.2

CHANGELOG:

1.2 - Created new structure for returned table
1.1 - Fixed base directory issue with the loadFile() function.

NOTE: This is a modified version of Alexander Makeev's Lua-only XML parser
found here: http://lua-users.org/wiki/LuaXml

--]]
xml = {}
function xml:newParser()

    XmlParser = {};

    function XmlParser:ToXmlString(value)
        value = string.gsub(value, "&", "&");
        value = string.gsub(value, "<", "&lt;");
        value = string.gsub(value, ">", "&gt;");
        value = string.gsub(value, "\"", "&quot;");
        value = string.gsub(value, "([^%w%&%;%p%\t% ])",
            function(c)
                return string.format("&#x%X;", string.byte(c))
            end);
        return value;
    end

    function XmlParser:FromXmlString(value)
        value = string.gsub(value, "&#x([%x]+)%;",
            function(h)
                return string.char(tonumber(h, 16))
            end);
        value = string.gsub(value, "&#([0-9]+)%;",
            function(h)
                return string.char(tonumber(h, 10))
            end);
        value = string.gsub(value, "&quot;", "\"");
        value = string.gsub(value, "&apos;", "'");
        value = string.gsub(value, "&gt;", ">");
        value = string.gsub(value, "&lt;", "<");
        value = string.gsub(value, "&amp;", "&");
        return value;
    end

    function XmlParser:ParseArgs(node, s)
        string.gsub(s, "([%w_]+)=([\"'])(.-)%2", function(w, _, a)
            node:addProperty(w, self:FromXmlString(a))
        end)
    end

    function XmlParser:ParseXmlText(xmlText)
        local stack = {}
        local top = xml:newNode()
        table.insert(stack, top)
        local ni, c, label, xarg, empty
        local i, j = 1, 1
        while true do
            ni, j, c, label, xarg, empty = string.find(xmlText,
	    "<(%/?)([%w_:]+)(.-)(%/?)>", i)
            if not ni then
		    break
	    end
            local text = string.sub(xmlText, i, ni - 1);
            if not string.find(text, "^%s*$") then
                local lVal = (top:value() or "") .. self:FromXmlString(text)
                stack[#stack]:setValue(lVal)
            end
            if empty == "/" then -- empty element tag
                local lNode = xml:newNode(label)
                self:ParseArgs(lNode, xarg)
                top:addChild(lNode)
            elseif c == "" then -- start tag
                local lNode = xml:newNode(label)
                self:ParseArgs(lNode, xarg)
                table.insert(stack, lNode)
		top = lNode
            else -- end tag
                local toclose = table.remove(stack) -- remove top
                top = stack[#stack]
                if #stack < 1 then
                    error("XmlParser: nothing to close with " .. label)
                end
                if toclose:name() ~= label then
                    error("XmlParser: trying to close " .. toclose.name ..
		    " with " .. label)
                end
                top:addChild(toclose)
            end
            i = j + 1
        end
        local text = string.sub(xmlText, i);
        if #stack > 1 then
            error("XmlParser: unclosed " .. stack[#stack]:name())
        end
        return top
    end

    function XmlParser:loadFile(xmlFilename, base)
        if not base then
            base = system.ResourceDirectory
        end
        local path = system.pathForFile(xmlFilename, base)
        local hFile, err = io.open(path, "r");
        if hFile and not err then
            local xmlText = hFile:read("*a"); -- read file content
            io.close(hFile);
            return self:ParseXmlText(xmlText), nil;
        else
            print(err)
            return nil
        end
    end
    return XmlParser
end

function xml:newNode(name)
    local node = {}
    node.___value = nil
    node.___name = name
    node.___children = {}
    node.___props = {}

    function node:value()
	    return self.___value
    end

    function node:setValue(val)
	    self.___value = val
    end

    function node:name()
	    return self.___name
    end

    function node:setName(name)
	    self.___name = name
    end

    function node:children()
	    return self.___children
    end

    function node:numChildren()
	    return #self.___children
    end

    function node:addChild(child)
        if self[child:name()] ~= nil then
            if type(self[child:name()].name) == "function" then
                local tempTable = {}
                table.insert(tempTable, self[child:name()])
                self[child:name()] = tempTable
            end
            table.insert(self[child:name()], child)
        else
            self[child:name()] = child
        end
        table.insert(self.___children, child)
    end

    function node:properties()
	    return self.___props
    end

    function node:numProperties()
	    return #self.___props
    end

    function node:addProperty(name, value)
        local lName = "@" .. name
        if self[lName] ~= nil then
            if type(self[lName]) == "string" then
                local tempTable = {}
                table.insert(tempTable, self[lName])
                self[lName] = tempTable
            end
            table.insert(self[lName], value)
        else
            self[lName] = value
        end
        table.insert(self.___props, { name = name, value = self[name] })
    end

    return node
end

return xml