line.go
func newLine(no int, str string, opts *Options, f *File) *line {
	return &line{
		no:     no,
		str:    str,
		indent: indent(str),
		tokens: strings.Split(strings.TrimLeft(str, space), space),
		opts:   opts,
		file:   f,
	}
}
func newLine(no int, str string, opts *Options, f *File) *line {
	return &line{
		no:     no,
		str:    str,
		indent: indent(str),
		tokens: strings.Split(strings.TrimLeft(str, space), space),
		opts:   opts,
		file:   f,
	}
}
// newLine creates and returns a line.