# Add line content to the active block parser
	#
	# We assume it can accept lines.
	private fun add_line do
		var content = null
		if column_is_in_tab then
			# Out column is in a partially consumed tab.
			# Expand the remaining columns to the next tab stop to spaces.
			var after_tab = index + 1
			var rest = line_string.substring(after_tab, line_string.length - after_tab)
			var spaces = column.columns_to_next_tab_stop
			var buffer = new Buffer
			for i in [0 .. spaces[ do
				buffer.add ' '
			end
			buffer.append(rest)
			content = buffer.write_to_string
		else
			content = line_string.substring(index, line_string.length - index)
		end
		active_block_parser.add_line(content)
	end