Recommended way of setting up multidimensional arrays

[Emmanuel Oga <emmanueloga@...>]

Hi,

I came up with this code for setting up dynamic, multidimensional arrays:

local dynArray

local dynArrayMeta = {
  __index = function(self, key)
    local new = dynArray()
    self[key] = new
    return new
  end
}

dynArray = function(initial)
  return setmetatable(initial or {}, dynArrayMeta)
end

-- usage:

    darr = dynArray()

    specialKey = {}

    for x = 1, 3 do
      for y = 1, 3 do
        for z = 1, 3 do
          darr[specialKey][x][y][z] = x .. " " .. y .. " " .. z
        end
      end
    end

    for x = 1, 3 do
      for y = 1, 3 do
        for z = 1, 3 do
          print(darr[specialKey][x][y][z])
        end
      end
    end


Usage, I believe, is straightforward. But since I see the question
about multidimensional arrays coming up frequently, I'm wondering if
I'm missing something with this code (e.g. any
performance/memory-waste considerations, possibility of hidden errors
appearing, etc...).

For instance one thing that could be considered problematic is
assigning to a dimension smaller than the biggest one:

    darr = dynArray()
    darr[1][2] = 3 -- 2 dimensions
    darr[1] = "oh-oh"  -- assigning to the first one breaks stuff.

but I'm really not worried a lot  about that one since I'm being
careful on how I use the array.

Greets.
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