# Does `value` contains valid XML markup?
	private fun check_html: Bool do
		var tags = new Array[String]
		var tmp = new FlatBuffer
		var pos = leading
		if pos + 1 < value.length and value[pos + 1] == '!' then
			if read_xml_comment(self, pos) > 0 then return true
		end
		pos = value.read_xml(tmp, pos, false)
		var tag: String
		if pos > -1 then
			tag = tmp.xml_tag
			if not tag.is_html_block then
				return false
			end
			if tag == "hr" then
				xml_end_line = self
				return true
			end
			tags.add tag
			var line: nullable MDLine = self
			while line != null do
				while pos < line.value.length and line.value[pos] != '<' do
					pos += 1
				end
				if pos >= line.value.length then
					if pos - 2 >= 0 and line.value[pos - 2] == '/' then
						tags.pop
						if tags.is_empty then
							xml_end_line = line
							break
						end
					end
					line = line.next
					pos = 0
				else
					tmp = new FlatBuffer
					var new_pos = line.value.read_xml(tmp, pos, false)
					if new_pos > 0 then
						tag = tmp.xml_tag
						if tag.is_html_block and not tag == "hr" then
							if tmp[1] == '/' then
								if tags.last != tag then
									return false
								end
								tags.pop
							else
								tags.add tag
							end
						end
						if tags.is_empty then
							xml_end_line = line
							break
						end
						pos = new_pos
					else
						pos += 1
					end
				end
			end
			return tags.is_empty
		end
		return false
	end