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

diff --git a/lib/trees/bintree.nit b/lib/trees/bintree.nit
index feb9671..447a33f 100644
--- a/lib/trees/bintree.nit
+++ b/lib/trees/bintree.nit
@@ -36,6 +36,7 @@ import abstract_tree
 #  * delete average O(lg n) worst O(n)
 #
 # Usage:
+#
 #     var tree = new BinTreeMap[Int, String]
 #     tree[1] = "n1"
 #     assert tree.min == "n1"
@@ -64,7 +65,7 @@ class BinTreeMap[K: Comparable, E]
 	#     assert not tree.has_key(0)
 	#     assert tree.has_key(2)
 	#     assert not tree.has_key(6)
-	redef fun has_key(key: K): Bool do
+	redef fun has_key(key) do
 		if is_empty then return false
 		var res = search_down(root.as(not null), key)
 		if res != null then
@@ -85,7 +86,7 @@ class BinTreeMap[K: Comparable, E]
 	#     assert tree[1] == "n1"
 	#     assert tree.has_key(1)
 	#     assert tree[2] == "n2"
-	redef fun [](key: K): E do
+	redef fun [](key) do
 		assert not_empty: not is_empty
 		if cache_node != null and cache_node.key == key then return cache_node.value
 		var res = search_down(root.as(not null), key)
@@ -93,7 +94,9 @@ class BinTreeMap[K: Comparable, E]
 		return res.value
 	end
 
-	protected fun search_down(from: N, key: K): nullable N do
+	# Search `key` in `from` and its children nodes.
+	protected fun search_down(from: N, key: nullable Object): nullable N do
+		if not key isa Comparable then return null
 		var cmp = key <=> from.key
 		if cmp == 0 then return from
 		if from.left != null and cmp < 0 then
@@ -115,6 +118,7 @@ class BinTreeMap[K: Comparable, E]
 		return min_from(root.as(not null)).value
 	end
 
+	# Get the left-most child from `node`.
 	protected fun min_from(node: N): N do
 		if node.left == null then return node
 		return min_from(node.left.as(not null))
@@ -131,6 +135,7 @@ class BinTreeMap[K: Comparable, E]
 		return max_from(root.as(not null)).value
 	end
 
+	# Get the right-most child from `node`.
 	protected fun max_from(node: N): N do
 		if node.right == null then return node
 		return max_from(node.right.as(not null))
@@ -148,6 +153,7 @@ class BinTreeMap[K: Comparable, E]
 		insert_node(new BinTreeNode[K, E](key, item))
 	end
 
+	# Add `node` in the tree.
 	protected fun insert_node(node: N) do
 		len += 1
 		if root == null then
@@ -311,6 +317,7 @@ class BinTreeMap[K: Comparable, E]
 		return sorted
 	end
 
+	# Sort the tree from `node` and place results in `sorted`.
 	protected fun sort_down(node: N, sorted: Array[E]) do
 		if node.left != null then sort_down(node.left.as(not null), sorted)
 		sorted.add(node.value)
@@ -323,6 +330,7 @@ class BinTreeMap[K: Comparable, E]
 		return "[{print_tree(root)}]"
 	end
 
+	# Print the tree starting from `node`.
 	protected fun print_tree(node: N): String do
 		var s = new FlatBuffer
 		s.append(node.to_s)
@@ -333,14 +341,15 @@ class BinTreeMap[K: Comparable, E]
 
 	redef fun show_dot do
 		assert not_empty: root != null
-		var f = new OProcess("dot", "-Txlib")
+		var f = new ProcessWriter("dot", "-Txlib")
 		f.write "digraph \{\n"
 		dot_down(root.as(not null), f)
 		f.write "\}\n"
 		f.close
 	end
 
-	protected fun dot_down(node: N, f: OProcess) do
+	# Translate the tree in dot format starting from `node`.
+	protected fun dot_down(node: N, f: ProcessWriter) do
 		if node.left != null then dot_down(node.left.as(not null), f)
 		f.write node.to_dot
 		if node.right != null then dot_down(node.right.as(not null), f)
@@ -371,15 +380,11 @@ end
 class BinTreeNode[K: Comparable, E]
 	super TreeNode[K, E]
 
-	private var prev: nullable BinTreeNode[K, E]
-	private var next: nullable BinTreeNode[K, E]
+	private var prev: nullable BinTreeNode[K, E] = null
+	private var next: nullable BinTreeNode[K, E] = null
 
 	redef type N: BinTreeNode[K, E]
 
-	init(key: K, item: E) do
-		super(key, item)
-	end
-
 	private var left_node: nullable N = null
 
 	# `left` tree node child (null if node has no left child)
@@ -448,11 +453,10 @@ end
 private class BinTreeMapIterator[K: Comparable, E]
 	super MapIterator[K, E]
 
-	var current: nullable BinTreeNode[K, E]
+	var tree: BinTreeMap[K, E]
+	var current: nullable BinTreeNode[K, E] = null
 
-	init(tree: BinTreeMap[K, E]) do
-		current = tree.first_node
-	end
+	init do current = tree.first_node
 
 	redef fun is_ok do return not current == null
 	redef fun next do current = current.next