Constructing tables in tables

["Henderson, Michael D" <michael.d.henderson@...>]

Hello. I'm using Lua 5.0.2 and I'm having trouble determining how to create nested tables. I'd looked at Chapter 10, Section 1 of Programming in Lua and was able to create a simple data description with a nested table like this

  --==========================================
  function comment(o)
    return o;
  end
  function data(o)
    print(" info: using following files...");
    for idx,file in ipairs(o.fileList) do
      print("       `" .. file .. "'");
    end;
  end
  --==========================================
  data {
    id = "one";
    fileList = { "aaa" , "bbb" , "ccc" };
    comment {
      author = "mike";
      text   = [[2005.02.20 - updated]];
    };
  };

I'd like to be able to have an array of the comments, but I can't figure out how to get there. How can I create one that allows me to have multiple instances of the table so that I can specify something like this

  data {
    id = "one";
    fileList = { "aaa" , "bbb" , "ccc" };
    comment {
      author = "mike";
      text   = [[2005.02.20 - updated]];
    };
    comment {
      author = "john";
      text   = [[2005.01.23 - created]];
    }
  };

It seemed to me that the function data(o) isn't called until the end of the data item. I'd thought that I could create a global (call it commentList) and tag each comment onto it

  commentList = {}; -- empty array
  idx = 0;
  function comment(o)
    commentList[idx] = o;
    idx = idx + 1;
  end
  function data(o)
    o.comments  = commentList; -- copy array
    commentList = {}; -- empty array
    idx = 0;
    print(" info: found " .. o.comments.getn .. " comments\n");
    print("       using following files...");
    for idx,file in ipairs(o.fileList) do
      print("       `" .. file .. "'");
    end;
  end

But that's not working. When I try treating o.comments as an array, I get an error (attempt to concatenate field `getn' (a nil value)).

Am I approaching this completely wrong?

Thanks,
Mike