enum class  io_format : unsigned char  {

    csv = 1,     // DataFrame specific csv format (not compatible with Pandas-like csv)
    csv2 = 2,    // Regular csv format (compatible with Pandas-like csv)
    json = 3,

    // DataFrame specific binary format.
    // This format is designed to maximize the speed of reading and writing the entire
    // data-frame at once.  It is also designed to maximize compression when compressed.
    //
    binary = 5,

    // These only apply to write (output) function. They are somewhat resource
    // consuming operations, especially for large datasets.
    // NOTE: Currently, special characters for these types are not escaped. So
    //       you better not have special chars.
    //       pretty_prt doesn't have any special characters.
    //
    pretty_prt = 6,
    markdown = 7,
    latex = 8,
    html = 9,
};