return source.readCodePointSet()
    }
  }

  /**
   * Reads a set of mapping lines like the following:
   *
   * ```
   *    180C; ; Map to nothing
   *    0041; 0061; Case map
   *    0390; 03B9 0308 0301; Case map
   * ```
   *
   * Each line maps from a single hexadecimal code point to zero or more hexadecimal code points.