X-Git-Url: http://nitlanguage.org

diff --git a/lib/standard/ropes.nit b/lib/standard/ropes.nit
index 940939d..f4221b0 100644
--- a/lib/standard/ropes.nit
+++ b/lib/standard/ropes.nit
@@ -111,6 +111,18 @@ abstract class Rope
 
 	redef fun length do return root.length
 
+	# Iterator on the nodes of the rope, in forward postfix order
+	private fun postfix(from: Int): Postfix do return new Postfix.from(self, from)
+
+	# Iterator on the leaves of the rope, forward order
+	private fun leaves(from: Int): LeavesIterator do return new LeavesIterator(self, from)
+
+	# Iterator on the substrings from 0, in forward order
+	fun substrings: IndexedIterator[Text] do return new SubstringsIterator(self, 0)
+
+	# Iterator on the substrings, starting at position `from`, in forward order
+	fun substrings_from(from: Int): IndexedIterator[Text] do return new SubstringsIterator(self, from)
+
 	# Path to the Leaf for `position`
 	private fun node_at(position: Int): Path
 	do
@@ -284,3 +296,228 @@ class RopeString
 	end
 end
 
+# Used to iterate on a Rope
+private class IteratorElement
+
+	init(e: RopeNode)
+	do
+		if e isa Leaf then
+			left = true
+			right = true
+		end
+		node = e
+	end
+
+	# The node being visited
+	var node: RopeNode
+	# If the node has a left child, was it visited ?
+	var left = false
+	# If the node has a right child, was it visited ?
+	var right = false
+	# Was the current node visited ?
+	var done = false
+end
+
+# Simple Postfix iterator on the nodes of a Rope
+private class Postfix
+	super IndexedIterator[RopeNode]
+
+	# Target Rope to iterate on
+	var target: Rope
+
+	# Current position in Rope
+	var pos: Int
+
+	# Visited nodes
+	var stack = new List[IteratorElement]
+
+	init from(tgt: Rope, pos: Int)
+	do
+		self.target = tgt
+		self.pos = pos
+		if pos < 0 or pos >= tgt.length then return
+		var path = tgt.node_at(pos)
+		self.pos -= path.offset
+		for i in path.stack do
+			var item = new IteratorElement(i.node)
+			item.left = true
+			if i.right then item.right = true
+			stack.push item
+		end
+		var item = new IteratorElement(path.leaf)
+		item.done = true
+		stack.push item
+	end
+
+	redef fun item
+	do
+		assert is_ok
+		return stack.last.node
+	end
+
+	redef fun is_ok do return not stack.is_empty
+
+	redef fun index do return pos
+
+	redef fun next do
+		if stack.is_empty then return
+		if pos > target.length-1 then
+			stack.clear
+			return
+		end
+		var lst = stack.last
+		if lst.done then
+			if lst.node isa Leaf then
+				pos += lst.node.length
+			end
+			stack.pop
+			next
+			return
+		end
+		if not lst.left then
+			lst.left = true
+			var nod = lst.node
+			if nod isa Concat and nod.left != null then
+				stack.push(new IteratorElement(nod.left.as(not null)))
+				next
+				return
+			end
+		end
+		if not lst.right then
+			lst.right = true
+			var nod = lst.node
+			if nod isa Concat and nod.right != null then
+				stack.push(new IteratorElement(nod.right.as(not null)))
+				next
+				return
+			end
+		end
+		lst.done = true
+	end
+end
+
+# Iterates on the leaves (substrings) of the Rope
+class LeavesIterator
+	super IndexedIterator[Leaf]
+
+	private var nodes: Postfix
+
+	init(tgt: Rope, pos: Int)
+	do
+		nodes = tgt.postfix(pos)
+	end
+
+	redef fun is_ok do return nodes.is_ok
+
+	redef fun item
+	do
+		assert is_ok
+		return nodes.item.as(Leaf)
+	end
+
+	redef fun index do return nodes.index
+
+	redef fun next
+	do
+		while nodes.is_ok do
+			nodes.next
+			if nodes.is_ok and nodes.item isa Leaf then break
+		end
+	end
+end
+
+# Uses the leaves and calculates a new substring on each iteration
+class SubstringsIterator
+	super IndexedIterator[Text]
+
+	private var nodes: IndexedIterator[Leaf]
+
+	# Current position in Rope
+	var pos: Int
+
+	# Current substring, computed from the current Leaf and indexes
+	var substring: Text
+
+	init(tgt: Rope, pos: Int)
+	do
+		nodes = tgt.leaves(pos)
+		self.pos = pos
+		if pos < 0 or pos >= tgt.length then return
+		make_substring
+	end
+
+	# Compute the bounds of the current substring and makes the substring
+	private fun make_substring
+	do
+		substring = nodes.item.str
+		var min = 0
+		var length = substring.length
+		if nodes.index < pos then
+			min = pos - nodes.index
+		end
+		substring = substring.substring(min, length)
+	end
+
+	redef fun is_ok do return nodes.is_ok
+
+	redef fun item
+	do
+		assert is_ok
+		return substring
+	end
+
+	redef fun index do return pos
+
+	redef fun next
+	do
+		pos += substring.length
+		nodes.next
+		if nodes.is_ok then make_substring
+	end
+
+end
+
+class RopeCharIterator
+	super IndexedIterator[Char]
+
+	var substrings: IndexedIterator[Text]
+
+	var pos: Int
+
+	var max: Int
+
+	var substr_iter: IndexedIterator[Char]
+
+	init(tgt: Rope, from: Int)
+	do
+		substrings = tgt.substrings_from(from)
+		max = tgt.length - 1
+		if not substrings.is_ok then
+			pos = tgt.length
+			return
+		end
+		pos = from
+		substr_iter = substrings.item.chars.iterator
+	end
+
+	redef fun item do return substr_iter.item
+
+	redef fun is_ok do return pos <= max
+
+	redef fun index do return pos
+
+	redef fun next
+	do
+		pos += 1
+		if substr_iter.is_ok then
+			substr_iter.next
+		end
+		if not substr_iter.is_ok then
+			substrings.next
+			if substrings.is_ok then
+				substr_iter = substrings.item.chars.iterator
+			end
+		end
+	end
+end
+