p.links = make(map[string]*Link)
	}
	p.links[label] = link
}

type line struct {
	spaces int
	i      int
	tab    int
	text   string
	nl     byte // newline character ending this line: \r or \n or zero for EOF
}

func (p *parseState) addLine(s line) {
	// Process continued prefixes.
	p.lineDepth = 0
	for ; p.lineDepth+1 < len(p.stack); p.lineDepth++ {
		old := s
		var ok bool