diff --git a/lib2/h3-compilers.ads b/lib2/h3-compilers.ads
index f5c3855..d57b3ba 100644
--- a/lib2/h3-compilers.ads
+++ b/lib2/h3-compilers.ads
@@ -1,5 +1,6 @@
 with H3.Runes;
 with H3.Strings;
+with H3.Trees;
 with Ada.Finalization;
 with Ada.Text_IO;
 
diff --git a/lib2/h3-trees.adb b/lib2/h3-trees.adb
index 115e9e8..35720c0 100644
--- a/lib2/h3-trees.adb
+++ b/lib2/h3-trees.adb
@@ -1,12 +1,14 @@
+with Ada.Unchecked_Deallocation;
 
 package body H3.Trees is
 
-	procedure Add_Node (Tr: in out Tree; N: in Node) is
-	begin 
-		--Tr.Nodes, 
-		
-		null;
-	end Add_Node;
+	procedure New_Node (Tr: in out Tree; Code: Node_Code) is
+		N: Node_Pointer;
+	begin
+		N := new Node(Code);
+		N.Next := Tr.Top;
+		Tr.Top := N;
+	end New_Node;
 
 	procedure Free_Node (Tr: in out Tree; N: in out Node) is
 	begin
@@ -16,4 +18,15 @@ package body H3.Trees is
 		null;
 	end Free_Node;
 
+	-- ------------------------------------------------------------------
+
+	overriding procedure Initialize (C: in out Tree) is
+	begin
+		null;
+	end Initialize;
+
+	overriding procedure Finalize (C: in out Tree) is
+	begin
+		null;
+	end Finalize;
 end H3.Trees;
diff --git a/lib2/h3-trees.ads b/lib2/h3-trees.ads
index 0e9642a..10783e1 100644
--- a/lib2/h3-trees.ads
+++ b/lib2/h3-trees.ads
@@ -1,23 +1,25 @@
-use H3.Arrays;
+with Ada.Finalization;
 
 package H3.Trees is
 
-	-- parse tree
-
 	--package A is new H3.Arrays(XXXX, 0);
 
 	type Node_Code is (
 		NODE_ASSIGN,
 		NODE_CALL,
-		NODE_CLASS
+		NODE_CLASS,
 		NODE_IF,
 		NODE_FUN,
 		NODE_VOID,
 		NODE_WHILE
 	);
 
+	type Node;
+	type Node_Pointer is access Node;
+
 	type Node(Code: Node_Code := NODE_VOID) is record
 		-- Loc: location.
+		Next: Node_Pointer;
 		case Code is
 			when NODE_ASSIGN =>
 				null;
@@ -33,11 +35,18 @@ package H3.Trees is
 				null;
 			when NODE_WHILE =>
 				null;
+		end case;
 	end record;
 
-	type Tree is record
-		Next_Node: System_Index := System_Index'First;
-		Toplevel_Node := Node
-	end Tree;
+	
 
+	-- parse tree
+	type Tree is new Ada.Finalization.Limited_Controlled with record
+		--Next_Node: System_Index := System_Index'First;
+		--Toplevel_Node := Node;
+		Top: Node_Pointer := null;
+	end record;
+
+	overriding procedure Initialize (C: in out Tree);
+	overriding procedure Finalize (C: in out Tree);
 end H3.Trees;