# Forward iterator on the chars of a `Rope`
private class RopeCharIterator
	super IndexedIterator[Char]

	# Position in current `String`
	var pns: Int is noautoinit
	# Current `String` being iterated on
	var str: String is noautoinit
	# Substrings of the Rope
	var subs: IndexedIterator[String] is noautoinit
	# Maximum position to iterate on (e.g. Rope.length)
	var max: Int is noautoinit
	# Position (char) in the Rope (0-indexed)
	var pos: Int is noautoinit

	init from(root: Concat, pos: Int) do
		subs = new RopeSubstrings.from(root, pos)
		pns = pos - subs.index
		self.pos = pos
		str = subs.item
		max = root.length - 1
	end

	redef fun item do return str[pns]

	redef fun is_ok do return pos <= max

	redef fun index do return pos

	redef fun next do
		pns += 1
		pos += 1
		if pns < subs.item.length then return
		if not subs.is_ok then return
		subs.next
		if not subs.is_ok then return
		str = subs.item
		pns = 0
	end
end