lib/trees: add generic and usefull services in TreeMapNode

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>

diff --git a/lib/trees/abstract_tree.nit b/lib/trees/abstract_tree.nit
index 38d22e4..02bc3b7 100644 (file)
--- a/lib/trees/abstract_tree.nit
+++ b/lib/trees/abstract_tree.nit
@@ -40,6 +40,7 @@ end
 # nodes are used to store values
 # * `E`: type of value
 class TreeNode[K: Comparable, E]
+       super Comparable
 
        # TreeNode type
        type N: TreeNode[K, E]
@@ -53,6 +54,17 @@ class TreeNode[K: Comparable, E]
        # Direct parent of this node (null if the node is root)
        var parent: nullable N = null is writable
 
+       # Depth in tree (length of the path from `self` to `root`)
+       fun depth: Int do
+               var node = parent
+               var i = 0
+               while node != null do
+                       node = node.parent
+                       i += 1
+               end
+               return i
+       end
+
        redef fun to_s do return "\{{value or else ""}\}"
 
        # Return dot representation of this node
@@ -63,4 +75,17 @@ class TreeNode[K: Comparable, E]
                if parent != null then res.append "\"{parent.as(not null)}\" -> \"{self}\"[dir=back];\n"
                return res.to_s
        end
+
+       redef type OTHER: N
+
+       # Nodes equality is done on `value` equality
+       #
+       # Redefine this method to change the default behavior.
+       redef fun ==(o) do
+               if not o isa N then return false
+               return self.value == o.value
+       end
+
+       # Nodes ordering is based on the `key`
+       redef fun <(o) do return self.key < o.key
 end