Lua Queue

-- Queue Table
-- Uses a table as stack, use <table>:push(value) and <table>:pop()
-- Lua 5.1 compatible

-- Create a Table with queue functions
function Create()

  -- queue table
  local t = {first = 0, last = -1}

  -- push a value on to the queue
  function t:push(...)
    if ... then
      local last
      local targs = {...}
      -- add values
      for _,v in ipairs(targs) do
        last = self.last + 1
        self.last = last
        self[last] = v
      end
    end
  end

  -- pop a value from the queue
  function t:pop(num)

    -- get num values from queue
    local num = num or 1

    -- return table
    local entries = {}
    local first

    -- get values into entries
    for i = 1, num do
      first = self.first

      -- get first entry
      if first <= self.last then
        table.insert(entries, self[first])
        -- remove last value

        self[first] = nil
        self.first = first + 1
      else
        break
      end
    end
    -- return unpacked entries
    return unpack(entries)
  end

  -- get entries
  function t:size()
    return self.last - self.first + 1
  end

  function t:empty()
    return self.first > self.last
  end

  return t
end