# Packs the content of a string in packs of `ln` chars.
	# This variant ensures that only the first element might be smaller than `ln`
	#
	# ~~~
	# var s = "abcdefghijklmnopqrstuvwxyz"
	# assert s.pack_r(4) == ["ab","cdef","ghij","klmn","opqr","stuv","wxyz"]
	# ~~~
	fun pack_r(ln: Int): Array[Text] do
		var st = length
		var retarr = new Array[Text].with_capacity(length / ln + length % ln)
		while st >= 0 do
			retarr.add(substring(st - ln, ln))
			st -= ln
		end
		return retarr.reversed
	end