Converting R1C1 style references for spreadsheets to AA1 style

gistfile1.rb

  # Converts row / column references to letter based column row references
  # for spreadsheet addressing. Assumes 0 base.
  def convert_row_column_to_cell_reference(r, c, ref)
    throw :column_reference_too_large if c > 255
    if c / 26 == 0
      ref << (c%26+65).chr+(r+1).to_s
    else
      ref << (c/26+64).chr
      convert_row_column_to_cell_reference(r, c%26, ref)
    end
  end