t3.lua

function characters_to_array(str, length)
  -- Returns an array where every (length) character are split into a new field
  -- of said array.
  if #str == 0 then return {} end
  
  local a,i = {},1
  repeat
    a[i] = str:sub(1,length)
    i = i + 1
    str = str:sub(length+1)
  until str == ''
  return a
end