Re: Parsing XML

On 7/9/07, Eva Schmidt <es@sol-3.de> wrote:

Hello everybody,

I'm currently using the simple XML-Parser from R. Ierusalimschy published on
http://lua-users.org/wiki/LuaXml. It works fine, but it puts every tag and
attribute in an XML-file onto a stack. So the structure gets a little bit large.
I would need a mor flat structure.
I tried to parse the stack and create a more flat Lua table instead. That worked
also, but the approach was very special to my problem (it parses the stack
recursively and collects label-value pairs and creates for any recursion a new
nested table).
The problem with this are the duplicate labels, that should create different
table instead of overwriting the old ones...

Does anybody have simliar problems and maybe some good ideas or approaches how
to convert the deep Lua stack to a flat table, including the dealing with
duplicate labels?

Here's some example code from me, but I'm not really happy with that:

--
-- parse stack and put instrument data in tables
--
-- counters
local c = 0
local x = 1
function parse_stack (tbl, result_tbl, tags)

    for j = 1, table.getn(tbl) do
       local value, label

         for i,v in pairs (tbl[j]) do

            if i == "label" then
               label = v
            elseif i == "xarg" then

               if (tbl[j][i].Value) then
                  value = tbl[j][i].Value
               end

            end
            if value == nil and label then
               -- create a separate table for a complete instrument description
               if label == "Instrument" then
                  c = 0
                  label = x
                  result_tbl[label] = {}
                  parse_stack (tbl[j], result_tbl[label],tags)
                  x = x + 1
               else
                  parse_stack (tbl[j], result_tbl, tags)
               end

            elseif value and label then
               build_instrument (label, value, result_tbl, c, tags)
            end
         end
    end
    -- in case of duplicate tags append a number to differentiate
    c = c + 1
end

--
-- utility for building an instrument
--
function build_instrument (label, value, tbl, count, tags)

    -- extend name of duplicate labels
    if (tbl[label]) then
       label = label .. "_" .. count
    end

    table.insert (tags, label)
    tbl[label] = value
end

Thanks for any idea!

All the best!
Eva