# Is this string blank?
	#
	# i.e. contains only spacing characters.
	private fun is_blank: Bool do
		for i in [0 .. length[ do
			var c = chars[i]
			if c == ' ' or c == '\t' or c == '\n' or c == '\r' then
				continue
			else
				return false
			end
		end
		return true
	end