code: func WalkLines(inpReader io.Reader, walkFn WalkLineFn) error {
  	reader := bufio.NewReader(inpReader)
  
  	var walkErr error
  	line, readErr := ReadLongLine(reader)
  	for ; walkErr == nil && readErr == nil; line, readErr = ReadLongLine(reader) {
  		walkErr = walkFn(line)
  	}
  
  	// if walk returned an error (other than io.EOF)
  	// return that error
  	if walkErr != nil && walkErr != io.EOF {
  		return walkErr
  	}
  
  	// otherwise, if there was a read error (except io.EOF), return that
  	if readErr != nil && readErr != io.EOF {
  		return readErr
  	}
  
  	return nil
  }
docs: // WalkLines ...