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[Gnash-commit] /srv/bzr/gnash/trunk r12223: Update tree.hh to latest ver


From: Benjamin Wolsey
Subject: [Gnash-commit] /srv/bzr/gnash/trunk r12223: Update tree.hh to latest version, also fixing clang++ warnings (unused
Date: Sat, 05 Jun 2010 12:24:26 +0200
User-agent: Bazaar (2.0.3)

------------------------------------------------------------
revno: 12223
committer: Benjamin Wolsey <address@hidden>
branch nick: trunk
timestamp: Sat 2010-06-05 12:24:26 +0200
message:
  Update tree.hh to latest version, also fixing clang++ warnings (unused
  variable for post-inc operators).
modified:
  libbase/tree.hh
=== modified file 'libbase/tree.hh'
--- a/libbase/tree.hh   2009-09-24 16:32:22 +0000
+++ b/libbase/tree.hh   2010-06-05 10:24:26 +0000
@@ -1,16 +1,14 @@
-/* 
-
-   $Id: tree.hh,v 1.7 2008/03/14 16:22:08 bwy Exp $
-
-   STL-like templated tree class.
-   Copyright (C) 2001-2006  Kasper Peeters <address@hidden>.
-
-*/
-
-/** \page tree.hh
+
+//     STL-like templated tree class.
+//
+// Copyright (C) 2001-2009 Kasper Peeters <address@hidden>
+// Distributed under the GNU General Public License version 3,
+// (eventually to be changed to the Boost Software License).
+
+/** \mainpage tree.hh
     \author   Kasper Peeters
-    \version  2.51
-    \date     28-Feb-2008
+    \version  2.65
+    \date     03-Apr-2009
     \see      http://www.aei.mpg.de/~peekas/tree/
     \see      http://www.aei.mpg.de/~peekas/tree/ChangeLog
 
@@ -23,39 +21,6 @@
 */
 
 
-/*
-   The tree.hh code is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; version 2 or 3.
-   
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-   
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-*/
-
-/** \todo 
-   - New-style move members are not completely finished yet.
-   - It would be good to have an iterator which can iterate over all
-     nodes below a given node. Something similar to the leaf iterator
-     we have right now, but not restricted to the leaves.
-   - If a range uses const iter_base& as end iterator, things will
-     inevitably go wrong, because upcast from iter_base to a non-sibling_iter
-     is incorrect. This upcast should be removed (and then all illegal uses
-     as previously in 'equal' will be flagged by the compiler). This requires
-     new copy constructors though.
-   - There's a bug in replace(sibling_iterator, ...) when the ranges
-     sit next to each other. Turned up in append_child(iter,iter)
-     but has been avoided now.
-   - "std::operator<" does not work correctly on our iterators, and for some
-     reason a globally defined template operator< did not get picked up. 
-     Using a comparison class now, but this should be investigated.
-*/
-
 #ifndef tree_hh_
 #define tree_hh_
 
@@ -65,6 +30,7 @@
 #include <iterator>
 #include <set>
 #include <queue>
+#include <algorithm>
 
 // HP-style construct/destroy have gone from the standard,
 // so here is a copy.
@@ -73,195 +39,193 @@
 
 template <class T1, class T2>
 void constructor(T1* p, T2& val) 
-   {
-   new ((void *) p) T1(val);
-   }
+       {
+       new ((void *) p) T1(val);
+       }
 
 template <class T1>
 void constructor(T1* p) 
-   {
-   new ((void *) p) T1;
-   }
+       {
+       new ((void *) p) T1;
+       }
 
 template <class T1>
 void destructor(T1* p)
-   {
-   p->~T1();
-   }
+       {
+       p->~T1();
+       }
 
 }
 
 /// A node in the tree, combining links to other nodes as well as the actual 
data.
 template<class T>
 class tree_node_ { // size: 5*4=20 bytes (on 32 bit arch), can be reduced by 8.
-   public:
-      tree_node_<T> *parent;
-      tree_node_<T> *first_child, *last_child;
-      tree_node_<T> *prev_sibling, *next_sibling;
-      T data;
+       public:
+               tree_node_<T> *parent;
+          tree_node_<T> *first_child, *last_child;
+               tree_node_<T> *prev_sibling, *next_sibling;
+               T data;
 }; // __attribute__((packed));
 
 template <class T, class tree_node_allocator = std::allocator<tree_node_<T> > >
 class tree {
-   protected:
-      typedef tree_node_<T> tree_node;
-   public:
-      /// Value of the data stored at a node.
-      typedef T value_type;
+       protected:
+               typedef tree_node_<T> tree_node;
+       public:
+               /// Value of the data stored at a node.
+               typedef T value_type;
 
-      class iterator_base;
-      class pre_order_iterator;
-      class post_order_iterator;
-      class sibling_iterator;
+               class iterator_base;
+               class pre_order_iterator;
+               class post_order_iterator;
+               class sibling_iterator;
       class leaf_iterator;
 
-      tree();
-      tree(const T&);
-      tree(const iterator_base&);
-      tree(const tree<T, tree_node_allocator>&);
-      ~tree();
-      void operator=(const tree<T, tree_node_allocator>&);
+               tree();
+               tree(const T&);
+               tree(const iterator_base&);
+               tree(const tree<T, tree_node_allocator>&);
+               ~tree();
+               void operator=(const tree<T, tree_node_allocator>&);
 
       /// Base class for iterators, only pointers stored, no traversal logic.
 #ifdef __SGI_STL_PORT
-      class iterator_base : public stlport::bidirectional_iterator<T, 
ptrdiff_t> {
+               class iterator_base : public stlport::bidirectional_iterator<T, 
ptrdiff_t> {
 #else
-      class iterator_base {
+               class iterator_base {
 #endif
-         public:
-            typedef T                               value_type;
-            typedef T*                              pointer;
-            typedef T&                              reference;
-            typedef size_t                          size_type;
-            typedef ptrdiff_t                       difference_type;
-            typedef std::bidirectional_iterator_tag iterator_category;
-
-            iterator_base();
-            iterator_base(tree_node *);
-
-            T&             operator*() const;
-            T*             operator->() const;
+                       public:
+                               typedef T                               
value_type;
+                               typedef T*                              pointer;
+                               typedef T&                              
reference;
+                               typedef size_t                          
size_type;
+                               typedef ptrdiff_t                       
difference_type;
+                               typedef std::bidirectional_iterator_tag 
iterator_category;
+
+                               iterator_base();
+                               iterator_base(tree_node *);
+
+                               T&             operator*() const;
+                               T*             operator->() const;
 
             /// When called, the next increment/decrement skips children of 
this node.
-            void         skip_children();
-            /// Number of children of the node pointed to by the iterator.
-            unsigned int number_of_children() const;
-
-            sibling_iterator begin() const;
-            sibling_iterator end() const;
-
-            tree_node *node;
-         protected:
-            bool skip_current_children_;
-      };
-
-      /// Depth-first iterator, first accessing the node, then its children.
-      class pre_order_iterator : public iterator_base { 
-         public:
-            pre_order_iterator();
-            pre_order_iterator(tree_node *);
-            pre_order_iterator(const iterator_base&);
-            pre_order_iterator(const sibling_iterator&);
-
-            bool    operator==(const pre_order_iterator&) const;
-            bool    operator!=(const pre_order_iterator&) const;
-            pre_order_iterator&  operator++();
-            pre_order_iterator&  operator--();
-            pre_order_iterator   operator++(int);
-            pre_order_iterator   operator--(int);
-            pre_order_iterator&  operator+=(unsigned int);
-            pre_order_iterator&  operator-=(unsigned int);
-      };
-
-      /// Depth-first iterator, first accessing the children, then the node 
itself.
-      class post_order_iterator : public iterator_base {
-         public:
-            post_order_iterator();
-            post_order_iterator(tree_node *);
-            post_order_iterator(const iterator_base&);
-            post_order_iterator(const sibling_iterator&);
-
-            bool    operator==(const post_order_iterator&) const;
-            bool    operator!=(const post_order_iterator&) const;
-            post_order_iterator&  operator++();
-            post_order_iterator&  operator--();
-            post_order_iterator   operator++(int);
-            post_order_iterator   operator--(int);
-            post_order_iterator&  operator+=(unsigned int);
-            post_order_iterator&  operator-=(unsigned int);
-
-            /// Set iterator to the first child as deep as possible down the 
tree.
-            void descend_all();
-      };
-
-      /// Breadth-first iterator, using a queue
-      class breadth_first_queued_iterator : public iterator_base {
-         public:
-            breadth_first_queued_iterator();
-            breadth_first_queued_iterator(tree_node *);
-            breadth_first_queued_iterator(const iterator_base&);
-
-            bool    operator==(const breadth_first_queued_iterator&) const;
-            bool    operator!=(const breadth_first_queued_iterator&) const;
-            breadth_first_queued_iterator&  operator++();
-            breadth_first_queued_iterator   operator++(int);
-            breadth_first_queued_iterator&  operator+=(unsigned int);
-
-         private:
-            std::queue<tree_node *> traversal_queue;
-      };
-
-      /// The default iterator types throughout the tree class.
-      typedef pre_order_iterator            iterator;
-      typedef breadth_first_queued_iterator breadth_first_iterator;
-
-      /// Iterator which traverses only the nodes at a given depth from the 
root.
-      class fixed_depth_iterator : public iterator_base {
-         public:
-            fixed_depth_iterator();
-            fixed_depth_iterator(tree_node *);
-            fixed_depth_iterator(const iterator_base&);
-            fixed_depth_iterator(const sibling_iterator&);
-            fixed_depth_iterator(const fixed_depth_iterator&);
-
-            bool    operator==(const fixed_depth_iterator&) const;
-            bool    operator!=(const fixed_depth_iterator&) const;
-            fixed_depth_iterator&  operator++();
-            fixed_depth_iterator&  operator--();
-            fixed_depth_iterator   operator++(int);
-            fixed_depth_iterator   operator--(int);
-            fixed_depth_iterator&  operator+=(unsigned int);
-            fixed_depth_iterator&  operator-=(unsigned int);
-
-            tree_node *first_parent_;
-         private:
-            void set_first_parent_();
-            void find_leftmost_parent_();
-      };
-
-      /// Iterator which traverses only the nodes which are siblings of each 
other.
-      class sibling_iterator : public iterator_base {
-         public:
-            sibling_iterator();
-            sibling_iterator(tree_node *);
-            sibling_iterator(const sibling_iterator&);
-            sibling_iterator(const iterator_base&);
-
-            bool    operator==(const sibling_iterator&) const;
-            bool    operator!=(const sibling_iterator&) const;
-            sibling_iterator&  operator++();
-            sibling_iterator&  operator--();
-            sibling_iterator   operator++(int);
-            sibling_iterator   operator--(int);
-            sibling_iterator&  operator+=(unsigned int);
-            sibling_iterator&  operator-=(unsigned int);
-
-            tree_node *range_first() const;
-            tree_node *range_last() const;
-            tree_node *parent_;
-         private:
-            void set_parent_();
-      };
+                               void         skip_children();
+                               void         skip_children(bool skip);
+                               /// Number of children of the node pointed to 
by the iterator.
+                               unsigned int number_of_children() const;
+
+                               sibling_iterator begin() const;
+                               sibling_iterator end() const;
+
+                               tree_node *node;
+                       protected:
+                               bool skip_current_children_;
+               };
+
+               /// Depth-first iterator, first accessing the node, then its 
children.
+               class pre_order_iterator : public iterator_base { 
+                       public:
+                               pre_order_iterator();
+                               pre_order_iterator(tree_node *);
+                               pre_order_iterator(const iterator_base&);
+                               pre_order_iterator(const sibling_iterator&);
+
+                               bool    operator==(const pre_order_iterator&) 
const;
+                               bool    operator!=(const pre_order_iterator&) 
const;
+                               pre_order_iterator&  operator++();
+                          pre_order_iterator&  operator--();
+                               pre_order_iterator   operator++(int);
+                               pre_order_iterator   operator--(int);
+                               pre_order_iterator&  operator+=(unsigned int);
+                               pre_order_iterator&  operator-=(unsigned int);
+               };
+
+               /// Depth-first iterator, first accessing the children, then 
the node itself.
+               class post_order_iterator : public iterator_base {
+                       public:
+                               post_order_iterator();
+                               post_order_iterator(tree_node *);
+                               post_order_iterator(const iterator_base&);
+                               post_order_iterator(const sibling_iterator&);
+
+                               bool    operator==(const post_order_iterator&) 
const;
+                               bool    operator!=(const post_order_iterator&) 
const;
+                               post_order_iterator&  operator++();
+                          post_order_iterator&  operator--();
+                               post_order_iterator   operator++(int);
+                               post_order_iterator   operator--(int);
+                               post_order_iterator&  operator+=(unsigned int);
+                               post_order_iterator&  operator-=(unsigned int);
+
+                               /// Set iterator to the first child as deep as 
possible down the tree.
+                               void descend_all();
+               };
+
+               /// Breadth-first iterator, using a queue
+               class breadth_first_queued_iterator : public iterator_base {
+                       public:
+                               breadth_first_queued_iterator();
+                               breadth_first_queued_iterator(tree_node *);
+                               breadth_first_queued_iterator(const 
iterator_base&);
+
+                               bool    operator==(const 
breadth_first_queued_iterator&) const;
+                               bool    operator!=(const 
breadth_first_queued_iterator&) const;
+                               breadth_first_queued_iterator&  operator++();
+                               breadth_first_queued_iterator   operator++(int);
+                               breadth_first_queued_iterator&  
operator+=(unsigned int);
+
+                       private:
+                               std::queue<tree_node *> traversal_queue;
+               };
+
+               /// The default iterator types throughout the tree class.
+               typedef pre_order_iterator            iterator;
+               typedef breadth_first_queued_iterator breadth_first_iterator;
+
+               /// Iterator which traverses only the nodes at a given depth 
from the root.
+               class fixed_depth_iterator : public iterator_base {
+                       public:
+                               fixed_depth_iterator();
+                               fixed_depth_iterator(tree_node *);
+                               fixed_depth_iterator(const iterator_base&);
+                               fixed_depth_iterator(const sibling_iterator&);
+                               fixed_depth_iterator(const 
fixed_depth_iterator&);
+
+                               bool    operator==(const fixed_depth_iterator&) 
const;
+                               bool    operator!=(const fixed_depth_iterator&) 
const;
+                               fixed_depth_iterator&  operator++();
+                          fixed_depth_iterator&  operator--();
+                               fixed_depth_iterator   operator++(int);
+                               fixed_depth_iterator   operator--(int);
+                               fixed_depth_iterator&  operator+=(unsigned int);
+                               fixed_depth_iterator&  operator-=(unsigned int);
+
+                               tree_node *top_node;
+               };
+
+               /// Iterator which traverses only the nodes which are siblings 
of each other.
+               class sibling_iterator : public iterator_base {
+                       public:
+                               sibling_iterator();
+                               sibling_iterator(tree_node *);
+                               sibling_iterator(const sibling_iterator&);
+                               sibling_iterator(const iterator_base&);
+
+                               bool    operator==(const sibling_iterator&) 
const;
+                               bool    operator!=(const sibling_iterator&) 
const;
+                               sibling_iterator&  operator++();
+                               sibling_iterator&  operator--();
+                               sibling_iterator   operator++(int);
+                               sibling_iterator   operator--(int);
+                               sibling_iterator&  operator+=(unsigned int);
+                               sibling_iterator&  operator-=(unsigned int);
+
+                               tree_node *range_first() const;
+                               tree_node *range_last() const;
+                               tree_node *parent_;
+                       private:
+                               void set_parent_();
+               };
 
       /// Iterator which traverses only the leaves.
       class leaf_iterator : public iterator_base {
@@ -279,30 +243,30 @@
             leaf_iterator   operator--(int);
             leaf_iterator&  operator+=(unsigned int);
             leaf_iterator&  operator-=(unsigned int);
-         private:
-            tree_node *top_node;
+                       private:
+                               tree_node *top_node;
       };
 
-      /// Return iterator to the beginning of the tree.
-      inline pre_order_iterator   begin() const;
-      /// Return iterator to the end of the tree.
-      inline pre_order_iterator   end() const;
-      /// Return post-order iterator to the beginning of the tree.
-      post_order_iterator  begin_post() const;
-      /// Return post-order end iterator of the tree.
-      post_order_iterator  end_post() const;
-      /// Return fixed-depth iterator to the first node at a given depth from 
the given iterator.
-      fixed_depth_iterator begin_fixed(const iterator_base&, unsigned int) 
const;
-      /// Return fixed-depth end iterator.
-      fixed_depth_iterator end_fixed(const iterator_base&, unsigned int) const;
-      /// Return breadth-first iterator to the first node at a given depth.
-      breadth_first_queued_iterator begin_breadth_first() const;
-      /// Return breadth-first end iterator.
-      breadth_first_queued_iterator end_breadth_first() const;
-      /// Return sibling iterator to the first child of given node.
-      sibling_iterator     begin(const iterator_base&) const;
-      /// Return sibling end iterator for children of given node.
-      sibling_iterator     end(const iterator_base&) const;
+               /// Return iterator to the beginning of the tree.
+               inline pre_order_iterator   begin() const;
+               /// Return iterator to the end of the tree.
+               inline pre_order_iterator   end() const;
+               /// Return post-order iterator to the beginning of the tree.
+               post_order_iterator  begin_post() const;
+               /// Return post-order end iterator of the tree.
+               post_order_iterator  end_post() const;
+               /// Return fixed-depth iterator to the first node at a given 
depth from the given iterator.
+               fixed_depth_iterator begin_fixed(const iterator_base&, unsigned 
int) const;
+               /// Return fixed-depth end iterator.
+               fixed_depth_iterator end_fixed(const iterator_base&, unsigned 
int) const;
+               /// Return breadth-first iterator to the first node at a given 
depth.
+               breadth_first_queued_iterator begin_breadth_first() const;
+               /// Return breadth-first end iterator.
+               breadth_first_queued_iterator end_breadth_first() const;
+               /// Return sibling iterator to the first child of given node.
+               sibling_iterator     begin(const iterator_base&) const;
+               /// Return sibling end iterator for children of given node.
+               sibling_iterator     end(const iterator_base&) const;
       /// Return leaf iterator to the first leaf of the tree.
       leaf_iterator   begin_leaf() const;
       /// Return leaf end iterator for entire tree.
@@ -312,193 +276,195 @@
       /// Return leaf end iterator for the subtree at the given node.
       leaf_iterator   end_leaf(const iterator_base& top) const;
 
-      /// Return iterator to the parent of a node.
-      template<typename iter> static iter parent(iter);
-      /// Return iterator to the previous sibling of a node.
-      template<typename iter> iter previous_sibling(iter) const;
-      /// Return iterator to the next sibling of a node.
-      template<typename iter> iter next_sibling(iter) const;
-      /// Return iterator to the next node at a given depth.
-      template<typename iter> iter next_at_same_depth(iter) const;
-
-      /// Erase all nodes of the tree.
-      void     clear();
-      /// Erase element at position pointed to by iterator, return incremented 
iterator.
-      template<typename iter> iter erase(iter);
-      /// Erase all children of the node pointed to by iterator.
-      void     erase_children(const iterator_base&);
-
-      /// Insert empty node as last/first child of node pointed to by position.
-      template<typename iter> iter append_child(iter position); 
-      template<typename iter> iter prepend_child(iter position); 
-      /// Insert node as last/first child of node pointed to by position.
-      template<typename iter> iter append_child(iter position, const T& x);
-      template<typename iter> iter prepend_child(iter position, const T& x);
-      /// Append the node (plus its children) at other_position as last/first 
child of position.
-      template<typename iter> iter append_child(iter position, iter 
other_position);
-      template<typename iter> iter prepend_child(iter position, iter 
other_position);
-      /// Append the nodes in the from-to range (plus their children) as 
last/first children of position.
-      template<typename iter> iter append_children(iter position, 
sibling_iterator from, sibling_iterator to);
-      template<typename iter> iter prepend_children(iter position, 
sibling_iterator from, sibling_iterator to);
-
-      /// Short-hand to insert topmost node in otherwise empty tree.
-      pre_order_iterator set_head(const T& x);
-      /// Insert node as previous sibling of node pointed to by position.
-      template<typename iter> iter insert(iter position, const T& x);
-      /// Specialisation of previous member.
-      sibling_iterator insert(sibling_iterator position, const T& x);
-      /// Insert node (with children) pointed to by subtree as previous 
sibling of node pointed to by position.
-      template<typename iter> iter insert_subtree(iter position, const 
iterator_base& subtree);
-      /// Insert node as next sibling of node pointed to by position.
-      template<typename iter> iter insert_after(iter position, const T& x);
-      /// Insert node (with children) pointed to by subtree as next sibling of 
node pointed to by position.
-      template<typename iter> iter insert_subtree_after(iter position, const 
iterator_base& subtree);
-
-      /// Replace node at 'position' with other node (keeping same children); 
'position' becomes invalid.
-      template<typename iter> iter replace(iter position, const T& x);
-      /// Replace node at 'position' with subtree starting at 'from' (do not 
erase subtree at 'from'); see above.
-      template<typename iter> iter replace(iter position, const iterator_base& 
from);
-      /// Replace string of siblings (plus their children) with copy of a new 
string (with children); see above
-      sibling_iterator replace(sibling_iterator orig_begin, sibling_iterator 
orig_end, 
-                               sibling_iterator new_begin,  sibling_iterator 
new_end); 
-
-      /// Move all children of node at 'position' to be siblings, returns 
position.
-      template<typename iter> iter flatten(iter position);
-      /// Move nodes in range to be children of 'position'.
-      template<typename iter> iter reparent(iter position, sibling_iterator 
begin, sibling_iterator end);
-      /// Move all child nodes of 'from' to be children of 'position'.
-      template<typename iter> iter reparent(iter position, iter from);
-
-      /// Replace node with a new node, making the old node a child of the new 
node.
-      template<typename iter> iter wrap(iter position, const T& x);
-
-      /// Move 'source' node (plus its children) to become the next sibling of 
'target'.
-      template<typename iter> iter move_after(iter target, iter source);
-      /// Move 'source' node (plus its children) to become the previous 
sibling of 'target'.
+               /// Return iterator to the parent of a node.
+               template<typename       iter> static iter parent(iter);
+               /// Return iterator to the previous sibling of a node.
+               template<typename iter> iter previous_sibling(iter) const;
+               /// Return iterator to the next sibling of a node.
+               template<typename iter> iter next_sibling(iter) const;
+               /// Return iterator to the next node at a given depth.
+               template<typename iter> iter next_at_same_depth(iter) const;
+
+               /// Erase all nodes of the tree.
+               void     clear();
+               /// Erase element at position pointed to by iterator, return 
incremented iterator.
+               template<typename iter> iter erase(iter);
+               /// Erase all children of the node pointed to by iterator.
+               void     erase_children(const iterator_base&);
+
+               /// Insert empty node as last/first child of node pointed to by 
position.
+               template<typename iter> iter append_child(iter position); 
+               template<typename iter> iter prepend_child(iter position); 
+               /// Insert node as last/first child of node pointed to by 
position.
+               template<typename iter> iter append_child(iter position, const 
T& x);
+               template<typename iter> iter prepend_child(iter position, const 
T& x);
+               /// Append the node (plus its children) at other_position as 
last/first child of position.
+               template<typename iter> iter append_child(iter position, iter 
other_position);
+               template<typename iter> iter prepend_child(iter position, iter 
other_position);
+               /// Append the nodes in the from-to range (plus their children) 
as last/first children of position.
+               template<typename iter> iter append_children(iter position, 
sibling_iterator from, sibling_iterator to);
+               template<typename iter> iter prepend_children(iter position, 
sibling_iterator from, sibling_iterator to);
+
+               /// Short-hand to insert topmost node in otherwise empty tree.
+               pre_order_iterator set_head(const T& x);
+               /// Insert node as previous sibling of node pointed to by 
position.
+               template<typename iter> iter insert(iter position, const T& x);
+               /// Specialisation of previous member.
+               sibling_iterator insert(sibling_iterator position, const T& x);
+               /// Insert node (with children) pointed to by subtree as 
previous sibling of node pointed to by position.
+               template<typename iter> iter insert_subtree(iter position, 
const iterator_base& subtree);
+               /// Insert node as next sibling of node pointed to by position.
+               template<typename iter> iter insert_after(iter position, const 
T& x);
+               /// Insert node (with children) pointed to by subtree as next 
sibling of node pointed to by position.
+               template<typename iter> iter insert_subtree_after(iter 
position, const iterator_base& subtree);
+
+               /// Replace node at 'position' with other node (keeping same 
children); 'position' becomes invalid.
+               template<typename iter> iter replace(iter position, const T& x);
+               /// Replace node at 'position' with subtree starting at 'from' 
(do not erase subtree at 'from'); see above.
+               template<typename iter> iter replace(iter position, const 
iterator_base& from);
+               /// Replace string of siblings (plus their children) with copy 
of a new string (with children); see above
+               sibling_iterator replace(sibling_iterator orig_begin, 
sibling_iterator orig_end, 
+                                                                               
 sibling_iterator new_begin,  sibling_iterator new_end); 
+
+               /// Move all children of node at 'position' to be siblings, 
returns position.
+               template<typename iter> iter flatten(iter position);
+               /// Move nodes in range to be children of 'position'.
+               template<typename iter> iter reparent(iter position, 
sibling_iterator begin, sibling_iterator end);
+               /// Move all child nodes of 'from' to be children of 'position'.
+               template<typename iter> iter reparent(iter position, iter from);
+
+               /// Replace node with a new node, making the old node a child 
of the new node.
+               template<typename iter> iter wrap(iter position, const T& x);
+
+               /// Move 'source' node (plus its children) to become the next 
sibling of 'target'.
+               template<typename iter> iter move_after(iter target, iter 
source);
+               /// Move 'source' node (plus its children) to become the 
previous sibling of 'target'.
       template<typename iter> iter move_before(iter target, iter source);
       sibling_iterator move_before(sibling_iterator target, sibling_iterator 
source);
-      /// Move 'source' node (plus its children) to become the node at 
'target' (erasing the node at 'target').
-      template<typename iter> iter move_ontop(iter target, iter source);
-
-      /// Merge with other tree, creating new branches and leaves only if they 
are not already present.
-      void     merge(sibling_iterator, sibling_iterator, sibling_iterator, 
sibling_iterator, 
-                     bool duplicate_leaves=false);
-      /// Sort (std::sort only moves values of nodes, this one moves children 
as well).
-      void     sort(sibling_iterator from, sibling_iterator to, bool 
deep=false);
-      template<class StrictWeakOrdering>
-      void     sort(sibling_iterator from, sibling_iterator to, 
StrictWeakOrdering comp, bool deep=false);
-      /// Compare two ranges of nodes (compares nodes as well as tree 
structure).
-      template<typename iter>
-      bool     equal(const iter& one, const iter& two, const iter& three) 
const;
-      template<typename iter, class BinaryPredicate>
-      bool     equal(const iter& one, const iter& two, const iter& three, 
BinaryPredicate) const;
-      template<typename iter>
-      bool     equal_subtree(const iter& one, const iter& two) const;
-      template<typename iter, class BinaryPredicate>
-      bool     equal_subtree(const iter& one, const iter& two, 
BinaryPredicate) const;
-      /// Extract a new tree formed by the range of siblings plus all their 
children.
-      tree     subtree(sibling_iterator from, sibling_iterator to) const;
-      void     subtree(tree&, sibling_iterator from, sibling_iterator to) 
const;
-      /// Exchange the node (plus subtree) with its sibling node (do nothing 
if no sibling present).
-      void     swap(sibling_iterator it);
-      /// Exchange two nodes (plus subtrees)
-      void     swap(iterator, iterator);
-      
-      /// Count the total number of nodes.
-      int      size() const;
-      /// Count the total number of nodes below the indicated node (plus one).
-      int      size(const iterator_base&) const;
-      /// Check if tree is empty.
-      bool     empty() const;
-      /// Compute the depth to the root.
-      int      depth(const iterator_base&) const;
-      /// Determine the maximal depth of the tree.
-      int      max_depth() const;
-      /// Determine the maximal depth of the tree below a given one.
-      int      max_depth(const iterator_base&) const;
-      /// Count the number of children of node at position.
-      static unsigned int number_of_children(const iterator_base&);
-      /// Count the number of 'next' siblings of node at iterator.
-      unsigned int number_of_siblings(const iterator_base&) const;
-      /// Determine whether node at position is in the subtrees with root in 
the range.
-      bool     is_in_subtree(const iterator_base& position, const 
iterator_base& begin, 
-                             const iterator_base& end) const;
-      /// Determine whether the iterator is an 'end' iterator and thus not 
actually pointing to a node.
-      bool     is_valid(const iterator_base&) const;
-
-      /// Determine the index of a node in the range of siblings to which it 
belongs.
-      unsigned int index(sibling_iterator it) const;
-      /// Inverse of 'index': return the n-th child of the node at position.
-      sibling_iterator  child(const iterator_base& position, unsigned int) 
const;
-      
-      /// Comparator class for iterators (compares pointer values; why doesn't 
this work automatically?)
-      class iterator_base_less {
-         public:
-            bool operator()(const typename tree<T, 
tree_node_allocator>::iterator_base& one,
-                            const typename tree<T, 
tree_node_allocator>::iterator_base& two) const
-               {
-               return one.node < two.node;
-               }
-      };
-      tree_node *head, *feet;    // head/feet are always dummy; if an iterator 
points to them it is invalid
-   private:
-      tree_node_allocator alloc_;
-      void head_initialise_();
-      void copy_(const tree<T, tree_node_allocator>& other);
+               /// Move 'source' node (plus its children) to become the node 
at 'target' (erasing the node at 'target').
+               template<typename iter> iter move_ontop(iter target, iter 
source);
+
+               /// Merge with other tree, creating new branches and leaves 
only if they are not already present.
+               void     merge(sibling_iterator, sibling_iterator, 
sibling_iterator, sibling_iterator, 
+                                                       bool 
duplicate_leaves=false);
+               /// Sort (std::sort only moves values of nodes, this one moves 
children as well).
+               void     sort(sibling_iterator from, sibling_iterator to, bool 
deep=false);
+               template<class StrictWeakOrdering>
+               void     sort(sibling_iterator from, sibling_iterator to, 
StrictWeakOrdering comp, bool deep=false);
+               /// Compare two ranges of nodes (compares nodes as well as tree 
structure).
+               template<typename iter>
+               bool     equal(const iter& one, const iter& two, const iter& 
three) const;
+               template<typename iter, class BinaryPredicate>
+               bool     equal(const iter& one, const iter& two, const iter& 
three, BinaryPredicate) const;
+               template<typename iter>
+               bool     equal_subtree(const iter& one, const iter& two) const;
+               template<typename iter, class BinaryPredicate>
+               bool     equal_subtree(const iter& one, const iter& two, 
BinaryPredicate) const;
+               /// Extract a new tree formed by the range of siblings plus all 
their children.
+               tree     subtree(sibling_iterator from, sibling_iterator to) 
const;
+               void     subtree(tree&, sibling_iterator from, sibling_iterator 
to) const;
+               /// Exchange the node (plus subtree) with its sibling node (do 
nothing if no sibling present).
+               void     swap(sibling_iterator it);
+               /// Exchange two nodes (plus subtrees)
+          void     swap(iterator, iterator);
+               
+               /// Count the total number of nodes.
+               size_t   size() const;
+               /// Count the total number of nodes below the indicated node 
(plus one).
+               size_t   size(const iterator_base&) const;
+               /// Check if tree is empty.
+               bool     empty() const;
+               /// Compute the depth to the root or to a fixed other iterator.
+               static int depth(const iterator_base&);
+               static int depth(const iterator_base&, const iterator_base&);
+               /// Determine the maximal depth of the tree. An empty tree has 
max_depth=-1.
+               int      max_depth() const;
+               /// Determine the maximal depth of the tree with top node at 
the given position.
+               int      max_depth(const iterator_base&) const;
+               /// Count the number of children of node at position.
+               static unsigned int number_of_children(const iterator_base&);
+               /// Count the number of siblings (left and right) of node at 
iterator. Total nodes at this level is +1.
+               unsigned int number_of_siblings(const iterator_base&) const;
+               /// Determine whether node at position is in the subtrees with 
root in the range.
+               bool     is_in_subtree(const iterator_base& position, const 
iterator_base& begin, 
+                                                                         const 
iterator_base& end) const;
+               /// Determine whether the iterator is an 'end' iterator and 
thus not actually pointing to a node.
+               bool     is_valid(const iterator_base&) const;
+
+               /// Determine the index of a node in the range of siblings to 
which it belongs.
+               unsigned int index(sibling_iterator it) const;
+               /// Inverse of 'index': return the n-th child of the node at 
position.
+               static sibling_iterator child(const iterator_base& position, 
unsigned int);
+               /// Return iterator to the sibling indicated by index
+               sibling_iterator sibling(const iterator_base& position, 
unsigned int);                                  
+               
+               /// Comparator class for iterators (compares pointer values; 
why doesn't this work automatically?)
+               class iterator_base_less {
+                       public:
+                               bool operator()(const typename tree<T, 
tree_node_allocator>::iterator_base& one,
+                                                                        const 
typename tree<T, tree_node_allocator>::iterator_base& two) const
+                                       {
+                                       return one.node < two.node;
+                                       }
+               };
+               tree_node *head, *feet;    // head/feet are always dummy; if an 
iterator points to them it is invalid
+       private:
+               tree_node_allocator alloc_;
+               void head_initialise_();
+               void copy_(const tree<T, tree_node_allocator>& other);
 
       /// Comparator class for two nodes of a tree (used for sorting and 
searching).
-      template<class StrictWeakOrdering>
-      class compare_nodes {
-         public:
-            compare_nodes(StrictWeakOrdering comp) : comp_(comp) {};
-            
-            bool operator()(const tree_node *a, const tree_node *b) 
-               {
-               static StrictWeakOrdering comp;
-               return comp(a->data, b->data);
-               }
-         private:
-            StrictWeakOrdering comp_;
-      };
+               template<class StrictWeakOrdering>
+               class compare_nodes {
+                       public:
+                               compare_nodes(StrictWeakOrdering comp) : 
comp_(comp) {};
+                               
+                               bool operator()(const tree_node *a, const 
tree_node *b) 
+                                       {
+                                       return comp_(a->data, b->data);
+                                       }
+                       private:
+                               StrictWeakOrdering comp_;
+               };
 };
 
 //template <class T, class tree_node_allocator>
 //class iterator_base_less {
-// public:
-//    bool operator()(const typename tree<T, 
tree_node_allocator>::iterator_base& one,
-//                  const typename tree<T, 
tree_node_allocator>::iterator_base& two) const
-//       {
-//       txtout << "operatorclass<" << one.node < two.node << std::endl;
-//       return one.node < two.node;
-//       }
+//     public:
+//             bool operator()(const typename tree<T, 
tree_node_allocator>::iterator_base& one,
+//                                               const typename tree<T, 
tree_node_allocator>::iterator_base& two) const
+//                     {
+//                     txtout << "operatorclass<" << one.node < two.node << 
std::endl;
+//                     return one.node < two.node;
+//                     }
 //};
 
 // template <class T, class tree_node_allocator>
 // bool operator<(const typename tree<T, tree_node_allocator>::iterator& one,
-//                const typename tree<T, tree_node_allocator>::iterator& two)
-//    {
-//    txtout << "operator< " << one.node < two.node << std::endl;
-//    if(one.node < two.node) return true;
-//    return false;
-//    }
+//                                     const typename tree<T, 
tree_node_allocator>::iterator& two)
+//     {
+//     txtout << "operator< " << one.node < two.node << std::endl;
+//     if(one.node < two.node) return true;
+//     return false;
+//     }
 // 
 // template <class T, class tree_node_allocator>
 // bool operator==(const typename tree<T, tree_node_allocator>::iterator& one,
-//                const typename tree<T, tree_node_allocator>::iterator& two)
-//    {
-//    txtout << "operator== " << one.node == two.node << std::endl;
-//    if(one.node == two.node) return true;
-//    return false;
-//    }
+//                                     const typename tree<T, 
tree_node_allocator>::iterator& two)
+//     {
+//     txtout << "operator== " << one.node == two.node << std::endl;
+//     if(one.node == two.node) return true;
+//     return false;
+//     }
 // 
 // template <class T, class tree_node_allocator>
 // bool operator>(const typename tree<T, tree_node_allocator>::iterator_base& 
one,
-//                const typename tree<T, tree_node_allocator>::iterator_base& 
two)
-//    {
-//    txtout << "operator> " << one.node < two.node << std::endl;
-//    if(one.node > two.node) return true;
-//    return false;
-//    }
+//                                     const typename tree<T, 
tree_node_allocator>::iterator_base& two)
+//     {
+//     txtout << "operator> " << one.node < two.node << std::endl;
+//     if(one.node > two.node) return true;
+//     return false;
+//     }
 
 
 
@@ -506,38 +472,38 @@
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::tree() 
-   {
-   head_initialise_();
-   }
+       {
+       head_initialise_();
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::tree(const T& x) 
-   {
-   head_initialise_();
-   set_head(x);
-   }
+       {
+       head_initialise_();
+       set_head(x);
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::tree(const iterator_base& other)
-   {
-   head_initialise_();
-   set_head((*other));
-   replace(begin(), other);
-   }
+       {
+       head_initialise_();
+       set_head((*other));
+       replace(begin(), other);
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::~tree()
-   {
-   clear();
-   alloc_.deallocate(head,1);
-   alloc_.deallocate(feet,1);
-   }
+       {
+       clear();
+       alloc_.deallocate(head,1);
+       alloc_.deallocate(feet,1);
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::head_initialise_() 
    { 
    head = alloc_.allocate(1,0); // MSVC does not have default second argument 
-   feet = alloc_.allocate(1,0);
+       feet = alloc_.allocate(1,0);
 
    head->parent=0;
    head->first_child=0;
@@ -545,204 +511,211 @@
    head->prev_sibling=0; //head;
    head->next_sibling=feet; //head;
 
-   feet->parent=0;
-   feet->first_child=0;
-   feet->last_child=0;
-   feet->prev_sibling=head;
-   feet->next_sibling=0;
+       feet->parent=0;
+       feet->first_child=0;
+       feet->last_child=0;
+       feet->prev_sibling=head;
+       feet->next_sibling=0;
    }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::operator=(const tree<T, 
tree_node_allocator>& other)
-   {
-   copy_(other);
-   }
+       {
+       copy_(other);
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::tree(const tree<T, tree_node_allocator>& other)
-   {
-   head_initialise_();
-   copy_(other);
-   }
+       {
+       head_initialise_();
+       copy_(other);
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::copy_(const tree<T, tree_node_allocator>& 
other) 
-   {
-   clear();
-   pre_order_iterator it=other.begin(), to=begin();
-   while(it!=other.end()) {
-      to=insert(to, (*it));
-      it.skip_children();
-      ++it;
-      }
-   to=begin();
-   it=other.begin();
-   while(it!=other.end()) {
-      to=replace(to, it);
-      to.skip_children();
-      it.skip_children();
-      ++to;
-      ++it;
-      }
-   }
+       {
+       clear();
+       pre_order_iterator it=other.begin(), to=begin();
+       while(it!=other.end()) {
+               to=insert(to, (*it));
+               it.skip_children();
+               ++it;
+               }
+       to=begin();
+       it=other.begin();
+       while(it!=other.end()) {
+               to=replace(to, it);
+               to.skip_children();
+               it.skip_children();
+               ++to;
+               ++it;
+               }
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::clear()
-   {
-   if(head)
-      while(head->next_sibling!=feet)
-         erase(pre_order_iterator(head->next_sibling));
-   }
+       {
+       if(head)
+               while(head->next_sibling!=feet)
+                       erase(pre_order_iterator(head->next_sibling));
+       }
 
 template<class T, class tree_node_allocator> 
 void tree<T, tree_node_allocator>::erase_children(const iterator_base& it)
-   {
-// std::cout << "erase_children " << it.node << std::endl;
-   if(it.node==0) return;
-
-   tree_node *cur=it.node->first_child;
-   tree_node *prev=0;
-
-   while(cur!=0) {
-      prev=cur;
-      cur=cur->next_sibling;
-      erase_children(pre_order_iterator(prev));
-      kp::destructor(&prev->data);
-      alloc_.deallocate(prev,1);
-      }
-   it.node->first_child=0;
-   it.node->last_child=0;
-// std::cout << "exit" << std::endl;
-   }
+       {
+//     std::cout << "erase_children " << it.node << std::endl;
+       if(it.node==0) return;
+
+       tree_node *cur=it.node->first_child;
+       tree_node *prev=0;
+
+       while(cur!=0) {
+               prev=cur;
+               cur=cur->next_sibling;
+               erase_children(pre_order_iterator(prev));
+               kp::destructor(&prev->data);
+               alloc_.deallocate(prev,1);
+               }
+       it.node->first_child=0;
+       it.node->last_child=0;
+//     std::cout << "exit" << std::endl;
+       }
 
 template<class T, class tree_node_allocator> 
 template<class iter>
 iter tree<T, tree_node_allocator>::erase(iter it)
-   {
-   tree_node *cur=it.node;
-   assert(cur!=head);
-   iter ret=it;
-   ret.skip_children();
-   ++ret;
-   erase_children(it);
-   if(cur->prev_sibling==0) {
-      cur->parent->first_child=cur->next_sibling;
-      }
-   else {
-      cur->prev_sibling->next_sibling=cur->next_sibling;
-      }
-   if(cur->next_sibling==0) {
-      cur->parent->last_child=cur->prev_sibling;
-      }
-   else {
-      cur->next_sibling->prev_sibling=cur->prev_sibling;
-      }
+       {
+       tree_node *cur=it.node;
+       assert(cur!=head);
+       iter ret=it;
+       ret.skip_children();
+       ++ret;
+       erase_children(it);
+       if(cur->prev_sibling==0) {
+               cur->parent->first_child=cur->next_sibling;
+               }
+       else {
+               cur->prev_sibling->next_sibling=cur->next_sibling;
+               }
+       if(cur->next_sibling==0) {
+               cur->parent->last_child=cur->prev_sibling;
+               }
+       else {
+               cur->next_sibling->prev_sibling=cur->prev_sibling;
+               }
 
-   kp::destructor(&cur->data);
+       kp::destructor(&cur->data);
    alloc_.deallocate(cur,1);
-   return ret;
-   }
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::pre_order_iterator tree<T, 
tree_node_allocator>::begin() const
-   {
-   return pre_order_iterator(head->next_sibling);
-   }
+       {
+       return pre_order_iterator(head->next_sibling);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::pre_order_iterator tree<T, 
tree_node_allocator>::end() const
-   {
-   return pre_order_iterator(feet);
-   }
+       {
+       return pre_order_iterator(feet);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::breadth_first_queued_iterator tree<T, 
tree_node_allocator>::begin_breadth_first() const
-   {
-   return breadth_first_queued_iterator(head->next_sibling);
-   }
+       {
+       return breadth_first_queued_iterator(head->next_sibling);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::breadth_first_queued_iterator tree<T, 
tree_node_allocator>::end_breadth_first() const
-   {
-   return breadth_first_queued_iterator();
-   }
+       {
+       return breadth_first_queued_iterator();
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::post_order_iterator tree<T, 
tree_node_allocator>::begin_post() const
-   {
-   tree_node *tmp=head->next_sibling;
-   if(tmp!=feet) {
-      while(tmp->first_child)
-         tmp=tmp->first_child;
-      }
-   return post_order_iterator(tmp);
-   }
+       {
+       tree_node *tmp=head->next_sibling;
+       if(tmp!=feet) {
+               while(tmp->first_child)
+                       tmp=tmp->first_child;
+               }
+       return post_order_iterator(tmp);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::post_order_iterator tree<T, 
tree_node_allocator>::end_post() const
-   {
-   return post_order_iterator(feet);
-   }
+       {
+       return post_order_iterator(feet);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::fixed_depth_iterator tree<T, 
tree_node_allocator>::begin_fixed(const iterator_base& pos, unsigned int dp) 
const
-   {
-   tree_node *tmp=pos.node;
-   unsigned int curdepth=0;
-   while(curdepth<dp) { // go down one level
-      while(tmp->first_child==0) {
-         if(tmp->next_sibling==0) {
-            // try to walk up and then right again
-            do {
-               tmp=tmp->parent;
+       {
+       typename tree<T, tree_node_allocator>::fixed_depth_iterator ret;
+       ret.top_node=pos.node;
+
+       tree_node *tmp=pos.node;
+       unsigned int curdepth=0;
+       while(curdepth<dp) { // go down one level
+               while(tmp->first_child==0) {
+                       if(tmp->next_sibling==0) {
+                               // try to walk up and then right again
+                               do {
+                                       if(tmp==ret.top_node)
+                                          throw std::range_error("tree: 
begin_fixed out of range");
+                                       tmp=tmp->parent;
                if(tmp==0) 
-                  throw std::range_error("tree: begin_fixed out of range");
+                                          throw std::range_error("tree: 
begin_fixed out of range");
                --curdepth;
-               } while(tmp->next_sibling==0);
-            }
-         tmp=tmp->next_sibling;
-         }
-      tmp=tmp->first_child;
-      ++curdepth;
-      }
-   return tmp;
-   }
+                                  } while(tmp->next_sibling==0);
+                               }
+                       tmp=tmp->next_sibling;
+                       }
+               tmp=tmp->first_child;
+               ++curdepth;
+               }
+
+       ret.node=tmp;
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::fixed_depth_iterator tree<T, 
tree_node_allocator>::end_fixed(const iterator_base& pos, unsigned int dp) const
-   {
-   assert(1==0); // FIXME: not correct yet: use is_valid() as a temporary 
workaround 
-   tree_node *tmp=pos.node;
-   unsigned int curdepth=1;
-   while(curdepth<dp) { // go down one level
-      while(tmp->first_child==0) {
-         tmp=tmp->next_sibling;
-         if(tmp==0)
-            throw std::range_error("tree: end_fixed out of range");
-         }
-      tmp=tmp->first_child;
-      ++curdepth;
-      }
-   return tmp;
-   }
+       {
+       assert(1==0); // FIXME: not correct yet: use is_valid() as a temporary 
workaround 
+       tree_node *tmp=pos.node;
+       unsigned int curdepth=1;
+       while(curdepth<dp) { // go down one level
+               while(tmp->first_child==0) {
+                       tmp=tmp->next_sibling;
+                       if(tmp==0)
+                               throw std::range_error("tree: end_fixed out of 
range");
+                       }
+               tmp=tmp->first_child;
+               ++curdepth;
+               }
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::begin(const iterator_base& pos) const
-   {
-   assert(pos.node!=0);
-   if(pos.node->first_child==0) {
-      return end(pos);
-      }
-   return pos.node->first_child;
-   }
+       {
+       assert(pos.node!=0);
+       if(pos.node->first_child==0) {
+               return end(pos);
+               }
+       return pos.node->first_child;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::end(const iterator_base& pos) const
-   {
-   sibling_iterator ret(0);
-   ret.parent_=pos.node;
-   return ret;
-   }
+       {
+       sibling_iterator ret(0);
+       ret.parent_=pos.node;
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::leaf_iterator tree<T, 
tree_node_allocator>::begin_leaf() const
@@ -764,9 +737,9 @@
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::leaf_iterator tree<T, 
tree_node_allocator>::begin_leaf(const iterator_base& top) const
    {
-   tree_node *tmp=top.node;
-   while(tmp->first_child)
-       tmp=tmp->first_child;
+       tree_node *tmp=top.node;
+       while(tmp->first_child)
+                tmp=tmp->first_child;
    return leaf_iterator(tmp, top.node);
    }
 
@@ -779,557 +752,564 @@
 template <class T, class tree_node_allocator>
 template <typename iter>
 iter tree<T, tree_node_allocator>::parent(iter position) 
-   {
-   assert(position.node!=0);
-   return iter(position.node->parent);
-   }
+       {
+       assert(position.node!=0);
+       return iter(position.node->parent);
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter>
 iter tree<T, tree_node_allocator>::previous_sibling(iter position) const
-   {
-   assert(position.node!=0);
-   iter ret(position);
-   ret.node=position.node->prev_sibling;
-   return ret;
-   }
+       {
+       assert(position.node!=0);
+       iter ret(position);
+       ret.node=position.node->prev_sibling;
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter>
 iter tree<T, tree_node_allocator>::next_sibling(iter position) const
-   {
-   assert(position.node!=0);
-   iter ret(position);
-   ret.node=position.node->next_sibling;
-   return ret;
-   }
+       {
+       assert(position.node!=0);
+       iter ret(position);
+       ret.node=position.node->next_sibling;
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter>
 iter tree<T, tree_node_allocator>::next_at_same_depth(iter position) const
-   {
-   assert(position.node!=0);
-   iter ret(position);
-
-   if(position.node->next_sibling) {
-      ret.node=position.node->next_sibling;
-      }
-   else { 
-      int relative_depth=0;
-      upper:
-      do {
-         ret.node=ret.node->parent;
-         if(ret.node==0) return ret;
-         --relative_depth;
-         } while(ret.node->next_sibling==0);
-      lower:
-      ret.node=ret.node->next_sibling;
-      while(ret.node->first_child==0) {
-         if(ret.node->next_sibling==0)
-            goto upper;
-         ret.node=ret.node->next_sibling;
-         if(ret.node==0) return ret;
-         }
-      while(relative_depth<0 && ret.node->first_child!=0) {
-         ret.node=ret.node->first_child;
-         ++relative_depth;
-         }
-      if(relative_depth<0) {
-         if(ret.node->next_sibling==0) goto upper;
-         else                          goto lower;
-         }
-      }
-   return ret;
-   }
+       {
+       // We make use of a temporary fixed_depth iterator to implement this.
+
+       typename tree<T, tree_node_allocator>::fixed_depth_iterator 
tmp(position.node);
+
+       ++tmp;
+       return iter(tmp);
+
+//     assert(position.node!=0);
+//     iter ret(position);
+//
+//     if(position.node->next_sibling) {
+//             ret.node=position.node->next_sibling;
+//             }
+//     else { 
+//             int relative_depth=0;
+//        upper:
+//             do {
+//                     ret.node=ret.node->parent;
+//                     if(ret.node==0) return ret;
+//                     --relative_depth;
+//                     } while(ret.node->next_sibling==0);
+//        lower:
+//             ret.node=ret.node->next_sibling;
+//             while(ret.node->first_child==0) {
+//                     if(ret.node->next_sibling==0)
+//                             goto upper;
+//                     ret.node=ret.node->next_sibling;
+//                     if(ret.node==0) return ret;
+//                     }
+//             while(relative_depth<0 && ret.node->first_child!=0) {
+//                     ret.node=ret.node->first_child;
+//                     ++relative_depth;
+//                     }
+//             if(relative_depth<0) {
+//                     if(ret.node->next_sibling==0) goto upper;
+//                     else                          goto lower;
+//                     }
+//             }
+//     return ret;
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter>
 iter tree<T, tree_node_allocator>::append_child(iter position)
-   {
-   assert(position.node!=head);
-   assert(position.node);
-
-   tree_node *tmp=alloc_.allocate(1,0);
-   kp::constructor(&tmp->data);
-   tmp->first_child=0;
-   tmp->last_child=0;
-
-   tmp->parent=position.node;
-   if(position.node->last_child!=0) {
-      position.node->last_child->next_sibling=tmp;
-      }
-   else {
-      position.node->first_child=tmp;
-      }
-   tmp->prev_sibling=position.node->last_child;
-   position.node->last_child=tmp;
-   tmp->next_sibling=0;
-   return tmp;
-   }
+       {
+       assert(position.node!=head);
+       assert(position.node);
+
+       tree_node *tmp=alloc_.allocate(1,0);
+       kp::constructor(&tmp->data);
+       tmp->first_child=0;
+       tmp->last_child=0;
+
+       tmp->parent=position.node;
+       if(position.node->last_child!=0) {
+               position.node->last_child->next_sibling=tmp;
+               }
+       else {
+               position.node->first_child=tmp;
+               }
+       tmp->prev_sibling=position.node->last_child;
+       position.node->last_child=tmp;
+       tmp->next_sibling=0;
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter>
 iter tree<T, tree_node_allocator>::prepend_child(iter position)
-   {
-   assert(position.node!=head);
-   assert(position.node);
-
-   tree_node *tmp=alloc_.allocate(1,0);
-   kp::constructor(&tmp->data);
-   tmp->first_child=0;
-   tmp->last_child=0;
-
-   tmp->parent=position.node;
-   if(position.node->first_child!=0) {
-      position.node->first_child->prev_sibling=tmp;
-      }
-   else {
-      position.node->last_child=tmp;
-      }
-   tmp->next_sibling=position.node->first_child;
-   position.node->prev_child=tmp;
-   tmp->prev_sibling=0;
-   return tmp;
-   }
+       {
+       assert(position.node!=head);
+       assert(position.node);
+
+       tree_node *tmp=alloc_.allocate(1,0);
+       kp::constructor(&tmp->data);
+       tmp->first_child=0;
+       tmp->last_child=0;
+
+       tmp->parent=position.node;
+       if(position.node->first_child!=0) {
+               position.node->first_child->prev_sibling=tmp;
+               }
+       else {
+               position.node->last_child=tmp;
+               }
+       tmp->next_sibling=position.node->first_child;
+       position.node->prev_child=tmp;
+       tmp->prev_sibling=0;
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::append_child(iter position, const T& x)
-   {
-   // If your program fails here you probably used 'append_child' to add the 
top
-   // node to an empty tree. From version 1.45 the top element should be added
-   // using 'insert'. See the documentation for further information, and sorry 
about
-   // the API change.
-   assert(position.node!=head);
-   assert(position.node);
-
-   tree_node* tmp = alloc_.allocate(1,0);
-   kp::constructor(&tmp->data, x);
-   tmp->first_child=0;
-   tmp->last_child=0;
-
-   tmp->parent=position.node;
-   if(position.node->last_child!=0) {
-      position.node->last_child->next_sibling=tmp;
-      }
-   else {
-      position.node->first_child=tmp;
-      }
-   tmp->prev_sibling=position.node->last_child;
-   position.node->last_child=tmp;
-   tmp->next_sibling=0;
-   return tmp;
-   }
+       {
+       // If your program fails here you probably used 'append_child' to add 
the top
+       // node to an empty tree. From version 1.45 the top element should be 
added
+       // using 'insert'. See the documentation for further information, and 
sorry about
+       // the API change.
+       assert(position.node!=head);
+       assert(position.node);
+
+       tree_node* tmp = alloc_.allocate(1,0);
+       kp::constructor(&tmp->data, x);
+       tmp->first_child=0;
+       tmp->last_child=0;
+
+       tmp->parent=position.node;
+       if(position.node->last_child!=0) {
+               position.node->last_child->next_sibling=tmp;
+               }
+       else {
+               position.node->first_child=tmp;
+               }
+       tmp->prev_sibling=position.node->last_child;
+       position.node->last_child=tmp;
+       tmp->next_sibling=0;
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::prepend_child(iter position, const T& x)
-   {
-   assert(position.node!=head);
-   assert(position.node);
-
-   tree_node* tmp = alloc_.allocate(1,0);
-   kp::constructor(&tmp->data, x);
-   tmp->first_child=0;
-   tmp->last_child=0;
-
-   tmp->parent=position.node;
-   if(position.node->first_child!=0) {
-      position.node->first_child->prev_sibling=tmp;
-      }
-   else {
-      position.node->last_child=tmp;
-      }
-   tmp->next_sibling=position.node->first_child;
-   position.node->first_child=tmp;
-   tmp->prev_sibling=0;
-   return tmp;
-   }
+       {
+       assert(position.node!=head);
+       assert(position.node);
+
+       tree_node* tmp = alloc_.allocate(1,0);
+       kp::constructor(&tmp->data, x);
+       tmp->first_child=0;
+       tmp->last_child=0;
+
+       tmp->parent=position.node;
+       if(position.node->first_child!=0) {
+               position.node->first_child->prev_sibling=tmp;
+               }
+       else {
+               position.node->last_child=tmp;
+               }
+       tmp->next_sibling=position.node->first_child;
+       position.node->first_child=tmp;
+       tmp->prev_sibling=0;
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::append_child(iter position, iter other)
-   {
-   assert(position.node!=head);
-   assert(position.node);
+       {
+       assert(position.node!=head);
+       assert(position.node);
 
-   sibling_iterator aargh=append_child(position, value_type());
-   return replace(aargh, other);
-   }
+       sibling_iterator aargh=append_child(position, value_type());
+       return replace(aargh, other);
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::prepend_child(iter position, iter other)
-   {
-   assert(position.node!=head);
-   assert(position.node);
+       {
+       assert(position.node!=head);
+       assert(position.node);
 
-   sibling_iterator aargh=prepend_child(position, value_type());
-   return replace(aargh, other);
-   }
+       sibling_iterator aargh=prepend_child(position, value_type());
+       return replace(aargh, other);
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::append_children(iter position, 
sibling_iterator from, sibling_iterator to)
-   {
-   assert(position.node!=head);
-   assert(position.node);
-
-   iter ret=from;
-
-   while(from!=to) {
-      insert_subtree(position.end(), from);
-      ++from;
-      }
-   return ret;
-   }
+       {
+       assert(position.node!=head);
+       assert(position.node);
+
+       iter ret=from;
+
+       while(from!=to) {
+               insert_subtree(position.end(), from);
+               ++from;
+               }
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::prepend_children(iter position, 
sibling_iterator from, sibling_iterator to)
-   {
-   assert(position.node!=head);
-   assert(position.node);
-
-   iter ret=from;
-
-   while(from!=to) {
-      insert_subtree(position.begin(), from);
-      ++from;
-      }
-   return ret;
-   }
+       {
+       assert(position.node!=head);
+       assert(position.node);
+
+       iter ret=from;
+
+       while(from!=to) {
+               insert_subtree(position.begin(), from);
+               ++from;
+               }
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::pre_order_iterator tree<T, 
tree_node_allocator>::set_head(const T& x)
-   {
-   assert(head->next_sibling==feet);
-   return insert(iterator(feet), x);
-   }
+       {
+       assert(head->next_sibling==feet);
+       return insert(iterator(feet), x);
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::insert(iter position, const T& x)
-   {
-   if(position.node==0) {
-      position.node=feet; // Backward compatibility: when calling insert on a 
null node,
-                          // insert before the feet.
-      }
-   tree_node* tmp = alloc_.allocate(1,0);
-   kp::constructor(&tmp->data, x);
-   tmp->first_child=0;
-   tmp->last_child=0;
-
-   tmp->parent=position.node->parent;
-   tmp->next_sibling=position.node;
-   tmp->prev_sibling=position.node->prev_sibling;
-   position.node->prev_sibling=tmp;
-
-   if(tmp->prev_sibling==0) {
-      if(tmp->parent) // when inserting nodes at the head, there is no parent
-         tmp->parent->first_child=tmp;
-      }
-   else
-      tmp->prev_sibling->next_sibling=tmp;
-   return tmp;
-   }
+       {
+       if(position.node==0) {
+               position.node=feet; // Backward compatibility: when calling 
insert on a null node,
+                                   // insert before the feet.
+               }
+       tree_node* tmp = alloc_.allocate(1,0);
+       kp::constructor(&tmp->data, x);
+       tmp->first_child=0;
+       tmp->last_child=0;
+
+       tmp->parent=position.node->parent;
+       tmp->next_sibling=position.node;
+       tmp->prev_sibling=position.node->prev_sibling;
+       position.node->prev_sibling=tmp;
+
+       if(tmp->prev_sibling==0) {
+               if(tmp->parent) // when inserting nodes at the head, there is 
no parent
+                       tmp->parent->first_child=tmp;
+               }
+       else
+               tmp->prev_sibling->next_sibling=tmp;
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::insert(sibling_iterator position, const T& x)
-   {
-   tree_node* tmp = alloc_.allocate(1,0);
-   kp::constructor(&tmp->data, x);
-   tmp->first_child=0;
-   tmp->last_child=0;
-
-   tmp->next_sibling=position.node;
-   if(position.node==0) { // iterator points to end of a subtree
-      tmp->parent=position.parent_;
-      tmp->prev_sibling=position.range_last();
-      tmp->parent->last_child=tmp;
-      }
-   else {
-      tmp->parent=position.node->parent;
-      tmp->prev_sibling=position.node->prev_sibling;
-      position.node->prev_sibling=tmp;
-      }
-
-   if(tmp->prev_sibling==0) {
-      if(tmp->parent) // when inserting nodes at the head, there is no parent
-         tmp->parent->first_child=tmp;
-      }
-   else
-      tmp->prev_sibling->next_sibling=tmp;
-   return tmp;
-   }
+       {
+       tree_node* tmp = alloc_.allocate(1,0);
+       kp::constructor(&tmp->data, x);
+       tmp->first_child=0;
+       tmp->last_child=0;
+
+       tmp->next_sibling=position.node;
+       if(position.node==0) { // iterator points to end of a subtree
+               tmp->parent=position.parent_;
+               tmp->prev_sibling=position.range_last();
+               tmp->parent->last_child=tmp;
+               }
+       else {
+               tmp->parent=position.node->parent;
+               tmp->prev_sibling=position.node->prev_sibling;
+               position.node->prev_sibling=tmp;
+               }
+
+       if(tmp->prev_sibling==0) {
+               if(tmp->parent) // when inserting nodes at the head, there is 
no parent
+                       tmp->parent->first_child=tmp;
+               }
+       else
+               tmp->prev_sibling->next_sibling=tmp;
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::insert_after(iter position, const T& x)
-   {
-   tree_node* tmp = alloc_.allocate(1,0);
-   kp::constructor(&tmp->data, x);
-   tmp->first_child=0;
-   tmp->last_child=0;
-
-   tmp->parent=position.node->parent;
-   tmp->prev_sibling=position.node;
-   tmp->next_sibling=position.node->next_sibling;
-   position.node->next_sibling=tmp;
-
-   if(tmp->next_sibling==0) {
-      if(tmp->parent) // when inserting nodes at the head, there is no parent
-         tmp->parent->last_child=tmp;
-      }
-   else {
-      tmp->next_sibling->prev_sibling=tmp;
-      }
-   return tmp;
-   }
+       {
+       tree_node* tmp = alloc_.allocate(1,0);
+       kp::constructor(&tmp->data, x);
+       tmp->first_child=0;
+       tmp->last_child=0;
+
+       tmp->parent=position.node->parent;
+       tmp->prev_sibling=position.node;
+       tmp->next_sibling=position.node->next_sibling;
+       position.node->next_sibling=tmp;
+
+       if(tmp->next_sibling==0) {
+               if(tmp->parent) // when inserting nodes at the head, there is 
no parent
+                       tmp->parent->last_child=tmp;
+               }
+       else {
+               tmp->next_sibling->prev_sibling=tmp;
+               }
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::insert_subtree(iter position, const 
iterator_base& subtree)
-   {
-   // insert dummy
-   iter it=insert(position, value_type());
-   // replace dummy with subtree
-   return replace(it, subtree);
-   }
+       {
+       // insert dummy
+       iter it=insert(position, value_type());
+       // replace dummy with subtree
+       return replace(it, subtree);
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::insert_subtree_after(iter position, const 
iterator_base& subtree)
-   {
-   // insert dummy
-   iter it=insert_after(position, value_type());
-   // replace dummy with subtree
-   return replace(it, subtree);
-   }
+       {
+       // insert dummy
+       iter it=insert_after(position, value_type());
+       // replace dummy with subtree
+       return replace(it, subtree);
+       }
 
 // template <class T, class tree_node_allocator>
 // template <class iter>
 // iter tree<T, tree_node_allocator>::insert_subtree(sibling_iterator 
position, iter subtree)
-//    {
-//    // insert dummy
-//    iter it(insert(position, value_type()));
-//    // replace dummy with subtree
-//    return replace(it, subtree);
-//    }
+//     {
+//     // insert dummy
+//     iter it(insert(position, value_type()));
+//     // replace dummy with subtree
+//     return replace(it, subtree);
+//     }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::replace(iter position, const T& x)
-   {
-   kp::destructor(&position.node->data);
-   kp::constructor(&position.node->data, x);
-   return position;
-   }
+       {
+       kp::destructor(&position.node->data);
+       kp::constructor(&position.node->data, x);
+       return position;
+       }
 
 template <class T, class tree_node_allocator>
 template <class iter>
 iter tree<T, tree_node_allocator>::replace(iter position, const iterator_base& 
from)
-   {
-   assert(position.node!=head);
-   tree_node *current_from=from.node;
-   tree_node *start_from=from.node;
-   tree_node *current_to  =position.node;
-
-   // replace the node at position with head of the replacement tree at from
-// std::cout << "warning!" << position.node << std::endl;
-   erase_children(position);  
-// std::cout << "no warning!" << std::endl;
-   tree_node* tmp = alloc_.allocate(1,0);
-   kp::constructor(&tmp->data, (*from));
-   tmp->first_child=0;
-   tmp->last_child=0;
-   if(current_to->prev_sibling==0) {
-      if(current_to->parent!=0)
-         current_to->parent->first_child=tmp;
-      }
-   else {
-      current_to->prev_sibling->next_sibling=tmp;
-      }
-   tmp->prev_sibling=current_to->prev_sibling;
-   if(current_to->next_sibling==0) {
-      if(current_to->parent!=0)
-         current_to->parent->last_child=tmp;
-      }
-   else {
-      current_to->next_sibling->prev_sibling=tmp;
-      }
-   tmp->next_sibling=current_to->next_sibling;
-   tmp->parent=current_to->parent;
-   kp::destructor(&current_to->data);
-   alloc_.deallocate(current_to,1);
-   current_to=tmp;
-   
-   // only at this stage can we fix 'last'
-   tree_node *last=from.node->next_sibling;
-
-   pre_order_iterator toit=tmp;
-   // copy all children
-   do {
-      assert(current_from!=0);
-      if(current_from->first_child != 0) {
-         current_from=current_from->first_child;
-         toit=append_child(toit, current_from->data);
-         }
-      else {
-         while(current_from->next_sibling==0 && current_from!=start_from) {
-            current_from=current_from->parent;
-            toit=parent(toit);
-            assert(current_from!=0);
-            }
-         current_from=current_from->next_sibling;
-         if(current_from!=last) {
-            toit=append_child(parent(toit), current_from->data);
-            }
-         }
-      } while(current_from!=last);
-
-   return current_to;
-   }
+       {
+       assert(position.node!=head);
+       tree_node *current_from=from.node;
+       tree_node *start_from=from.node;
+       tree_node *current_to  =position.node;
+
+       // replace the node at position with head of the replacement tree at 
from
+//     std::cout << "warning!" << position.node << std::endl;
+       erase_children(position);       
+//     std::cout << "no warning!" << std::endl;
+       tree_node* tmp = alloc_.allocate(1,0);
+       kp::constructor(&tmp->data, (*from));
+       tmp->first_child=0;
+       tmp->last_child=0;
+       if(current_to->prev_sibling==0) {
+               if(current_to->parent!=0)
+                       current_to->parent->first_child=tmp;
+               }
+       else {
+               current_to->prev_sibling->next_sibling=tmp;
+               }
+       tmp->prev_sibling=current_to->prev_sibling;
+       if(current_to->next_sibling==0) {
+               if(current_to->parent!=0)
+                       current_to->parent->last_child=tmp;
+               }
+       else {
+               current_to->next_sibling->prev_sibling=tmp;
+               }
+       tmp->next_sibling=current_to->next_sibling;
+       tmp->parent=current_to->parent;
+       kp::destructor(&current_to->data);
+       alloc_.deallocate(current_to,1);
+       current_to=tmp;
+       
+       // only at this stage can we fix 'last'
+       tree_node *last=from.node->next_sibling;
+
+       pre_order_iterator toit=tmp;
+       // copy all children
+       do {
+               assert(current_from!=0);
+               if(current_from->first_child != 0) {
+                       current_from=current_from->first_child;
+                       toit=append_child(toit, current_from->data);
+                       }
+               else {
+                       while(current_from->next_sibling==0 && 
current_from!=start_from) {
+                               current_from=current_from->parent;
+                               toit=parent(toit);
+                               assert(current_from!=0);
+                               }
+                       current_from=current_from->next_sibling;
+                       if(current_from!=last) {
+                               toit=append_child(parent(toit), 
current_from->data);
+                               }
+                       }
+               } while(current_from!=last);
+
+       return current_to;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::replace(
-   sibling_iterator orig_begin, 
-   sibling_iterator orig_end, 
-   sibling_iterator new_begin, 
-   sibling_iterator new_end)
-   {
-   tree_node *orig_first=orig_begin.node;
-   tree_node *new_first=new_begin.node;
-   tree_node *orig_last=orig_first;
-   while((++orig_begin)!=orig_end)
-      orig_last=orig_last->next_sibling;
-   tree_node *new_last=new_first;
-   while((++new_begin)!=new_end)
-      new_last=new_last->next_sibling;
-
-   // insert all siblings in new_first..new_last before orig_first
-   bool first=true;
-   pre_order_iterator ret;
-   while(1==1) {
-      pre_order_iterator tt=insert_subtree(pre_order_iterator(orig_first), 
pre_order_iterator(new_first));
-      if(first) {
-         ret=tt;
-         first=false;
-         }
-      if(new_first==new_last)
-         break;
-      new_first=new_first->next_sibling;
-      }
-
-   // erase old range of siblings
-   bool last=false;
-   tree_node *next=orig_first;
-   while(1==1) {
-      if(next==orig_last) 
-         last=true;
-      next=next->next_sibling;
-      erase((pre_order_iterator)orig_first);
-      if(last) 
-         break;
-      orig_first=next;
-      }
-   return ret;
-   }
+       sibling_iterator orig_begin, 
+       sibling_iterator orig_end, 
+       sibling_iterator new_begin, 
+       sibling_iterator new_end)
+       {
+       tree_node *orig_first=orig_begin.node;
+       tree_node *new_first=new_begin.node;
+       tree_node *orig_last=orig_first;
+       while((++orig_begin)!=orig_end)
+               orig_last=orig_last->next_sibling;
+       tree_node *new_last=new_first;
+       while((++new_begin)!=new_end)
+               new_last=new_last->next_sibling;
+
+       // insert all siblings in new_first..new_last before orig_first
+       bool first=true;
+       pre_order_iterator ret;
+       while(1==1) {
+               pre_order_iterator 
tt=insert_subtree(pre_order_iterator(orig_first), 
pre_order_iterator(new_first));
+               if(first) {
+                       ret=tt;
+                       first=false;
+                       }
+               if(new_first==new_last)
+                       break;
+               new_first=new_first->next_sibling;
+               }
+
+       // erase old range of siblings
+       bool last=false;
+       tree_node *next=orig_first;
+       while(1==1) {
+               if(next==orig_last) 
+                       last=true;
+               next=next->next_sibling;
+               erase((pre_order_iterator)orig_first);
+               if(last) 
+                       break;
+               orig_first=next;
+               }
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter>
 iter tree<T, tree_node_allocator>::flatten(iter position)
-   {
-   if(position.node->first_child==0)
-      return position;
-
-   tree_node *tmp=position.node->first_child;
-   while(tmp) {
-      tmp->parent=position.node->parent;
-      tmp=tmp->next_sibling;
-      } 
-   if(position.node->next_sibling) {
-      position.node->last_child->next_sibling=position.node->next_sibling;
-      position.node->next_sibling->prev_sibling=position.node->last_child;
-      }
-   else {
-      position.node->parent->last_child=position.node->last_child;
-      }
-   position.node->next_sibling=position.node->first_child;
-   position.node->next_sibling->prev_sibling=position.node;
-   position.node->first_child=0;
-   position.node->last_child=0;
-
-   return position;
-   }
+       {
+       if(position.node->first_child==0)
+               return position;
+
+       tree_node *tmp=position.node->first_child;
+       while(tmp) {
+               tmp->parent=position.node->parent;
+               tmp=tmp->next_sibling;
+               } 
+       if(position.node->next_sibling) {
+               
position.node->last_child->next_sibling=position.node->next_sibling;
+               
position.node->next_sibling->prev_sibling=position.node->last_child;
+               }
+       else {
+               position.node->parent->last_child=position.node->last_child;
+               }
+       position.node->next_sibling=position.node->first_child;
+       position.node->next_sibling->prev_sibling=position.node;
+       position.node->first_child=0;
+       position.node->last_child=0;
+
+       return position;
+       }
 
 
 template <class T, class tree_node_allocator>
 template <typename iter>
 iter tree<T, tree_node_allocator>::reparent(iter position, sibling_iterator 
begin, sibling_iterator end)
-   {
-   tree_node *first=begin.node;
-   tree_node *last=first;
-
-   assert(first!=position.node);
-   
-   if(begin==end) return begin;
-   // determine last node
-   while((++begin)!=end) {
-      last=last->next_sibling;
-      }
-   // move subtree
-   if(first->prev_sibling==0) {
-      first->parent->first_child=last->next_sibling;
-      }
-   else {
-      first->prev_sibling->next_sibling=last->next_sibling;
-      }
-   if(last->next_sibling==0) {
-      last->parent->last_child=first->prev_sibling;
-      }
-   else {
-      last->next_sibling->prev_sibling=first->prev_sibling;
-      }
-   if(position.node->first_child==0) {
-      position.node->first_child=first;
-      position.node->last_child=last;
-      first->prev_sibling=0;
-      }
-   else {
-      position.node->last_child->next_sibling=first;
-      first->prev_sibling=position.node->last_child;
-      position.node->last_child=last;
-      }
-   last->next_sibling=0;
-
-   tree_node *pos=first;
-   while(1==1) {
-      pos->parent=position.node;
-      if(pos==last) break;
-      pos=pos->next_sibling;
-      }
-
-   return first;
-   }
+       {
+       tree_node *first=begin.node;
+       tree_node *last=first;
+
+       assert(first!=position.node);
+       
+       if(begin==end) return begin;
+       // determine last node
+       while((++begin)!=end) {
+               last=last->next_sibling;
+               }
+       // move subtree
+       if(first->prev_sibling==0) {
+               first->parent->first_child=last->next_sibling;
+               }
+       else {
+               first->prev_sibling->next_sibling=last->next_sibling;
+               }
+       if(last->next_sibling==0) {
+               last->parent->last_child=first->prev_sibling;
+               }
+       else {
+               last->next_sibling->prev_sibling=first->prev_sibling;
+               }
+       if(position.node->first_child==0) {
+               position.node->first_child=first;
+               position.node->last_child=last;
+               first->prev_sibling=0;
+               }
+       else {
+               position.node->last_child->next_sibling=first;
+               first->prev_sibling=position.node->last_child;
+               position.node->last_child=last;
+               }
+       last->next_sibling=0;
+
+       tree_node *pos=first;
+   for(;;) {
+               pos->parent=position.node;
+               if(pos==last) break;
+               pos=pos->next_sibling;
+               }
+
+       return first;
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter> iter tree<T, tree_node_allocator>::reparent(iter 
position, iter from)
-   {
-   if(from.node->first_child==0) return position;
-   return reparent(position, from.node->first_child, end(from));
-   }
+       {
+       if(from.node->first_child==0) return position;
+       return reparent(position, from.node->first_child, end(from));
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter> iter tree<T, tree_node_allocator>::wrap(iter 
position, const T& x)
-   {
-   assert(position.node!=0);
-   sibling_iterator fr=position, to=position;
-   ++to;
-   iter ret = insert(position, x);
-   reparent(ret, fr, to);
-   return ret;
-   }
+       {
+       assert(position.node!=0);
+       sibling_iterator fr=position, to=position;
+       ++to;
+       iter ret = insert(position, x);
+       reparent(ret, fr, to);
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter> iter tree<T, tree_node_allocator>::move_after(iter 
target, iter source)
@@ -1340,9 +1320,9 @@
    assert(src);
 
    if(dst==src) return source;
-   if(dst->next_sibling)
-      if(dst->next_sibling==src) // already in the right spot
-         return source;
+       if(dst->next_sibling)
+               if(dst->next_sibling==src) // already in the right spot
+                       return source;
 
    // take src out of the tree
    if(src->prev_sibling!=0) src->prev_sibling->next_sibling=src->next_sibling;
@@ -1369,9 +1349,9 @@
    assert(src);
 
    if(dst==src) return source;
-   if(dst->prev_sibling)
-      if(dst->prev_sibling==src) // already in the right spot
-         return source;
+       if(dst->prev_sibling)
+               if(dst->prev_sibling==src) // already in the right spot
+                       return source;
 
    // take src out of the tree
    if(src->prev_sibling!=0) src->prev_sibling->next_sibling=src->next_sibling;
@@ -1392,465 +1372,507 @@
 // specialisation for sibling_iterators
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::move_before(sibling_iterator target, 
-                                                                               
          sibling_iterator source)
-   {
-   tree_node *dst=target.node;
-   tree_node *src=source.node;
-   tree_node *dst_prev_sibling;
-   if(dst==0) { // must then be an end iterator
-      dst_prev_sibling=target.parent_->last_child;
-      assert(dst_prev_sibling);
-      }
-   else dst_prev_sibling=dst->prev_sibling;
-   assert(src);
-
-   if(dst==src) return source;
-   if(dst_prev_sibling)
-      if(dst_prev_sibling==src) // already in the right spot
-         return source;
-
-   // take src out of the tree
-   if(src->prev_sibling!=0) src->prev_sibling->next_sibling=src->next_sibling;
-   else                     src->parent->first_child=src->next_sibling;
-   if(src->next_sibling!=0) src->next_sibling->prev_sibling=src->prev_sibling;
-   else                     src->parent->last_child=src->prev_sibling;
-
-   // connect it to the new point
-   if(dst_prev_sibling!=0) dst_prev_sibling->next_sibling=src;
-   else                    target.parent_->first_child=src;
-   src->prev_sibling=dst_prev_sibling;
-   if(dst) {
-      dst->prev_sibling=src;
-      src->parent=dst->parent;
-      }
-   src->next_sibling=dst;
-   return src;
-   }
+                                                                               
                                                                                
                                                                          
sibling_iterator source)
+       {
+       tree_node *dst=target.node;
+       tree_node *src=source.node;
+       tree_node *dst_prev_sibling;
+       if(dst==0) { // must then be an end iterator
+               dst_prev_sibling=target.parent_->last_child;
+               assert(dst_prev_sibling);
+               }
+       else dst_prev_sibling=dst->prev_sibling;
+       assert(src);
+
+       if(dst==src) return source;
+       if(dst_prev_sibling)
+               if(dst_prev_sibling==src) // already in the right spot
+                       return source;
+
+       // take src out of the tree
+       if(src->prev_sibling!=0) 
src->prev_sibling->next_sibling=src->next_sibling;
+       else                     src->parent->first_child=src->next_sibling;
+       if(src->next_sibling!=0) 
src->next_sibling->prev_sibling=src->prev_sibling;
+       else                     src->parent->last_child=src->prev_sibling;
+
+       // connect it to the new point
+       if(dst_prev_sibling!=0) dst_prev_sibling->next_sibling=src;
+       else                    target.parent_->first_child=src;
+       src->prev_sibling=dst_prev_sibling;
+       if(dst) {
+               dst->prev_sibling=src;
+               src->parent=dst->parent;
+               }
+       src->next_sibling=dst;
+       return src;
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter> iter tree<T, tree_node_allocator>::move_ontop(iter 
target, iter source)
-   {
-   tree_node *dst=target.node;
-   tree_node *src=source.node;
-   assert(dst);
-   assert(src);
-
-   if(dst==src) return source;
-
-   // remember connection points
-   tree_node *b_prev_sibling=dst->prev_sibling;
-   tree_node *b_next_sibling=dst->next_sibling;
-   tree_node *b_parent=dst->parent;
-
-   // remove target
-   erase(target);
-
-   // take src out of the tree
-   if(src->prev_sibling!=0) src->prev_sibling->next_sibling=src->next_sibling;
-   else                     src->parent->first_child=src->next_sibling;
-   if(src->next_sibling!=0) src->next_sibling->prev_sibling=src->prev_sibling;
-   else                     src->parent->last_child=src->prev_sibling;
-
-   // connect it to the new point
-   if(b_prev_sibling!=0) b_prev_sibling->next_sibling=src;
-   else                  b_parent->first_child=src;
-   if(b_next_sibling!=0) b_next_sibling->prev_sibling=src;
-   else                  b_parent->last_child=src;
-   src->prev_sibling=b_prev_sibling;
-   src->next_sibling=b_next_sibling;
-   src->parent=b_parent;
-   return src;
-   }
+       {
+       tree_node *dst=target.node;
+       tree_node *src=source.node;
+       assert(dst);
+       assert(src);
+
+       if(dst==src) return source;
+
+       // remember connection points
+       tree_node *b_prev_sibling=dst->prev_sibling;
+       tree_node *b_next_sibling=dst->next_sibling;
+       tree_node *b_parent=dst->parent;
+
+       // remove target
+       erase(target);
+
+       // take src out of the tree
+       if(src->prev_sibling!=0) 
src->prev_sibling->next_sibling=src->next_sibling;
+       else                     src->parent->first_child=src->next_sibling;
+       if(src->next_sibling!=0) 
src->next_sibling->prev_sibling=src->prev_sibling;
+       else                     src->parent->last_child=src->prev_sibling;
+
+       // connect it to the new point
+       if(b_prev_sibling!=0) b_prev_sibling->next_sibling=src;
+       else                  b_parent->first_child=src;
+       if(b_next_sibling!=0) b_next_sibling->prev_sibling=src;
+       else                  b_parent->last_child=src;
+       src->prev_sibling=b_prev_sibling;
+       src->next_sibling=b_next_sibling;
+       src->parent=b_parent;
+       return src;
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::merge(sibling_iterator to1,   
sibling_iterator to2,
-                                          sibling_iterator from1, 
sibling_iterator from2,
-                                          bool duplicate_leaves)
-   {
-   sibling_iterator fnd;
-   while(from1!=from2) {
-      if((fnd=std::find(to1, to2, (*from1))) != to2) { // element found
-         if(from1.begin()==from1.end()) { // full depth reached
-            if(duplicate_leaves)
-               append_child(parent(to1), (*from1));
-            }
-         else { // descend further
-            merge(fnd.begin(), fnd.end(), from1.begin(), from1.end(), 
duplicate_leaves);
-            }
-         }
-      else { // element missing
-         insert_subtree(to2, from1);
-         }
-      ++from1;
-      }
-   }
+                                                                               
                                sibling_iterator from1, sibling_iterator from2,
+                                                                               
                                bool duplicate_leaves)
+       {
+       sibling_iterator fnd;
+       while(from1!=from2) {
+               if((fnd=std::find(to1, to2, (*from1))) != to2) { // element 
found
+                       if(from1.begin()==from1.end()) { // full depth reached
+                               if(duplicate_leaves)
+                                       append_child(parent(to1), (*from1));
+                               }
+                       else { // descend further
+                               merge(fnd.begin(), fnd.end(), from1.begin(), 
from1.end(), duplicate_leaves);
+                               }
+                       }
+               else { // element missing
+                       insert_subtree(to2, from1);
+                       }
+               ++from1;
+               }
+       }
 
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::sort(sibling_iterator from, 
sibling_iterator to, bool deep)
-   {
-   std::less<T> comp;
-   sort(from, to, comp, deep);
-   }
+       {
+       std::less<T> comp;
+       sort(from, to, comp, deep);
+       }
 
 template <class T, class tree_node_allocator>
 template <class StrictWeakOrdering>
 void tree<T, tree_node_allocator>::sort(sibling_iterator from, 
sibling_iterator to, 
-                                        StrictWeakOrdering comp, bool deep)
-   {
-   if(from==to) return;
-   // make list of sorted nodes
-   // CHECK: if multiset stores equivalent nodes in the order in which they
-   // are inserted, then this routine should be called 'stable_sort'.
-   std::multiset<tree_node *, compare_nodes<StrictWeakOrdering> > nodes(comp);
-   sibling_iterator it=from, it2=to;
-   while(it != to) {
-      nodes.insert(it.node);
-      ++it;
-      }
-   // reassemble
-   --it2;
-
-   // prev and next are the nodes before and after the sorted range
-   tree_node *prev=from.node->prev_sibling;
-   tree_node *next=it2.node->next_sibling;
-   typename std::multiset<tree_node *, compare_nodes<StrictWeakOrdering> 
>::iterator nit=nodes.begin(), eit=nodes.end();
-   if(prev==0) {
-      if((*nit)->parent!=0) // to catch "sorting the head" situations, when 
there is no parent
-         (*nit)->parent->first_child=(*nit);
-      }
-   else prev->next_sibling=(*nit);
-
-   --eit;
-   while(nit!=eit) {
-      (*nit)->prev_sibling=prev;
-      if(prev)
-         prev->next_sibling=(*nit);
-      prev=(*nit);
-      ++nit;
-      }
-   // prev now points to the last-but-one node in the sorted range
-   if(prev)
-      prev->next_sibling=(*eit);
-
-   // eit points to the last node in the sorted range.
-   (*eit)->next_sibling=next;
+                                                                               
                         StrictWeakOrdering comp, bool deep)
+       {
+       if(from==to) return;
+       // make list of sorted nodes
+       // CHECK: if multiset stores equivalent nodes in the order in which they
+       // are inserted, then this routine should be called 'stable_sort'.
+       std::multiset<tree_node *, compare_nodes<StrictWeakOrdering> > 
nodes(comp);
+       sibling_iterator it=from, it2=to;
+       while(it != to) {
+               nodes.insert(it.node);
+               ++it;
+               }
+       // reassemble
+       --it2;
+
+       // prev and next are the nodes before and after the sorted range
+       tree_node *prev=from.node->prev_sibling;
+       tree_node *next=it2.node->next_sibling;
+       typename std::multiset<tree_node *, compare_nodes<StrictWeakOrdering> 
>::iterator nit=nodes.begin(), eit=nodes.end();
+       if(prev==0) {
+               if((*nit)->parent!=0) // to catch "sorting the head" 
situations, when there is no parent
+                       (*nit)->parent->first_child=(*nit);
+               }
+       else prev->next_sibling=(*nit);
+
+       --eit;
+       while(nit!=eit) {
+               (*nit)->prev_sibling=prev;
+               if(prev)
+                       prev->next_sibling=(*nit);
+               prev=(*nit);
+               ++nit;
+               }
+       // prev now points to the last-but-one node in the sorted range
+       if(prev)
+               prev->next_sibling=(*eit);
+
+       // eit points to the last node in the sorted range.
+       (*eit)->next_sibling=next;
    (*eit)->prev_sibling=prev; // missed in the loop above
-   if(next==0) {
-      if((*eit)->parent!=0) // to catch "sorting the head" situations, when 
there is no parent
-         (*eit)->parent->last_child=(*eit);
-      }
-   else next->prev_sibling=(*eit);
+       if(next==0) {
+               if((*eit)->parent!=0) // to catch "sorting the head" 
situations, when there is no parent
+                       (*eit)->parent->last_child=(*eit);
+               }
+       else next->prev_sibling=(*eit);
 
-   if(deep) {  // sort the children of each node too
-      sibling_iterator bcs(*nodes.begin());
-      sibling_iterator ecs(*eit);
-      ++ecs;
-      while(bcs!=ecs) {
-         sort(begin(bcs), end(bcs), comp, deep);
-         ++bcs;
-         }
-      }
-   }
+       if(deep) {      // sort the children of each node too
+               sibling_iterator bcs(*nodes.begin());
+               sibling_iterator ecs(*eit);
+               ++ecs;
+               while(bcs!=ecs) {
+                       sort(begin(bcs), end(bcs), comp, deep);
+                       ++bcs;
+                       }
+               }
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter>
 bool tree<T, tree_node_allocator>::equal(const iter& one_, const iter& two, 
const iter& three_) const
-   {
-   std::equal_to<T> comp;
-   return equal(one_, two, three_, comp);
-   }
+       {
+       std::equal_to<T> comp;
+       return equal(one_, two, three_, comp);
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter>
 bool tree<T, tree_node_allocator>::equal_subtree(const iter& one_, const iter& 
two_) const
-   {
-   std::equal_to<T> comp;
-   return equal_subtree(one_, two_, comp);
-   }
+       {
+       std::equal_to<T> comp;
+       return equal_subtree(one_, two_, comp);
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter, class BinaryPredicate>
 bool tree<T, tree_node_allocator>::equal(const iter& one_, const iter& two, 
const iter& three_, BinaryPredicate fun) const
-   {
-   pre_order_iterator one(one_), three(three_);
+       {
+       pre_order_iterator one(one_), three(three_);
 
-// if(one==two && is_valid(three) && three.number_of_children()!=0)
-//    return false;
-   while(one!=two && is_valid(three)) {
-      if(!fun(*one,*three))
-         return false;
-      if(one.number_of_children()!=three.number_of_children()) 
-         return false;
-      ++one;
-      ++three;
-      }
-   return true;
-   }
+//     if(one==two && is_valid(three) && three.number_of_children()!=0)
+//             return false;
+       while(one!=two && is_valid(three)) {
+               if(!fun(*one,*three))
+                       return false;
+               if(one.number_of_children()!=three.number_of_children()) 
+                       return false;
+               ++one;
+               ++three;
+               }
+       return true;
+       }
 
 template <class T, class tree_node_allocator>
 template <typename iter, class BinaryPredicate>
 bool tree<T, tree_node_allocator>::equal_subtree(const iter& one_, const iter& 
two_, BinaryPredicate fun) const
-   {
-   pre_order_iterator one(one_), two(two_);
+       {
+       pre_order_iterator one(one_), two(two_);
 
-   if(!fun(*one,*two)) return false;
-   if(number_of_children(one)!=number_of_children(two)) return false;
-   return equal(begin(one),end(one),begin(two),fun);
-   }
+       if(!fun(*one,*two)) return false;
+       if(number_of_children(one)!=number_of_children(two)) return false;
+       return equal(begin(one),end(one),begin(two),fun);
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator> tree<T, 
tree_node_allocator>::subtree(sibling_iterator from, sibling_iterator to) const
-   {
-   tree tmp;
-   tmp.set_head(value_type());
-   tmp.replace(tmp.begin(), tmp.end(), from, to);
-   return tmp;
-   }
+       {
+       tree tmp;
+       tmp.set_head(value_type());
+       tmp.replace(tmp.begin(), tmp.end(), from, to);
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::subtree(tree& tmp, sibling_iterator from, 
sibling_iterator to) const
-   {
-   tmp.set_head(value_type());
-   tmp.replace(tmp.begin(), tmp.end(), from, to);
-   }
-
-template <class T, class tree_node_allocator>
-int tree<T, tree_node_allocator>::size() const
-   {
-   int i=0;
-   pre_order_iterator it=begin(), eit=end();
-   while(it!=eit) {
-      ++i;
-      ++it;
-      }
-   return i;
-   }
-
-template <class T, class tree_node_allocator>
-int tree<T, tree_node_allocator>::size(const iterator_base& top) const
-   {
-   int i=0;
-   pre_order_iterator it=top, eit=top;
-   eit.skip_children();
-   ++eit;
-   while(it!=eit) {
-      ++i;
-      ++it;
-      }
-   return i;
-   }
+       {
+       tmp.set_head(value_type());
+       tmp.replace(tmp.begin(), tmp.end(), from, to);
+       }
+
+template <class T, class tree_node_allocator>
+size_t tree<T, tree_node_allocator>::size() const
+       {
+       size_t i=0;
+       pre_order_iterator it=begin(), eit=end();
+       while(it!=eit) {
+               ++i;
+               ++it;
+               }
+       return i;
+       }
+
+template <class T, class tree_node_allocator>
+size_t tree<T, tree_node_allocator>::size(const iterator_base& top) const
+       {
+       size_t i=0;
+       pre_order_iterator it=top, eit=top;
+       eit.skip_children();
+       ++eit;
+       while(it!=eit) {
+               ++i;
+               ++it;
+               }
+       return i;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::empty() const
-   {
-   pre_order_iterator it=begin(), eit=end();
-   return (it==eit);
-   }
-
-template <class T, class tree_node_allocator>
-int tree<T, tree_node_allocator>::depth(const iterator_base& it) const
-   {
-   tree_node* pos=it.node;
-   assert(pos!=0);
-   int ret=0;
-   while(pos->parent!=0) {
-      pos=pos->parent;
-      ++ret;
-      }
-   return ret;
-   }
+       {
+       pre_order_iterator it=begin(), eit=end();
+       return (it==eit);
+       }
+
+template <class T, class tree_node_allocator>
+int tree<T, tree_node_allocator>::depth(const iterator_base& it) 
+       {
+       tree_node* pos=it.node;
+       assert(pos!=0);
+       int ret=0;
+       while(pos->parent!=0) {
+               pos=pos->parent;
+               ++ret;
+               }
+       return ret;
+       }
+
+template <class T, class tree_node_allocator>
+int tree<T, tree_node_allocator>::depth(const iterator_base& it, const 
iterator_base& root) 
+       {
+       tree_node* pos=it.node;
+       assert(pos!=0);
+       int ret=0;
+       while(pos->parent!=0 && pos!=root.node) {
+               pos=pos->parent;
+               ++ret;
+               }
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 int tree<T, tree_node_allocator>::max_depth() const
-   {
-   return max_depth(begin());
-   }
+       {
+       int maxd=-1;
+       for(tree_node *it = head->next_sibling; it!=feet; it=it->next_sibling)
+               maxd=std::max(maxd, max_depth(it));
+
+       return maxd;
+       }
 
 
 template <class T, class tree_node_allocator>
 int tree<T, tree_node_allocator>::max_depth(const iterator_base& pos) const
-   {
-   tree_node *tmp=pos.node;
-   int curdepth=0, maxdepth=0;
-   while(true) { // try to walk the bottom of the tree
-      while(tmp->first_child==0) {
-         if(tmp==pos.node) return maxdepth;
-         if(tmp->next_sibling==0) {
-            // try to walk up and then right again
-            do {
-               tmp=tmp->parent;
+       {
+       tree_node *tmp=pos.node;
+
+       if(tmp==0 || tmp==head || tmp==feet) return -1;
+
+       int curdepth=0, maxdepth=0;
+       while(true) { // try to walk the bottom of the tree
+               while(tmp->first_child==0) {
+                       if(tmp==pos.node) return maxdepth;
+                       if(tmp->next_sibling==0) {
+                               // try to walk up and then right again
+                               do {
+                                       tmp=tmp->parent;
                if(tmp==0) return maxdepth;
                --curdepth;
-               } while(tmp->next_sibling==0);
-            }
+                                  } while(tmp->next_sibling==0);
+                               }
          if(tmp==pos.node) return maxdepth;
-         tmp=tmp->next_sibling;
-         }
-      tmp=tmp->first_child;
-      ++curdepth;
-      maxdepth=std::max(curdepth, maxdepth);
-      } 
-   }
+                       tmp=tmp->next_sibling;
+                       }
+               tmp=tmp->first_child;
+               ++curdepth;
+               maxdepth=std::max(curdepth, maxdepth);
+               } 
+       }
 
 template <class T, class tree_node_allocator>
 unsigned int tree<T, tree_node_allocator>::number_of_children(const 
iterator_base& it) 
-   {
-   tree_node *pos=it.node->first_child;
-   if(pos==0) return 0;
-   
-   unsigned int ret=1;
-//   while(pos!=it.node->last_child) {
-//      ++ret;
-//      pos=pos->next_sibling;
-//      }
-   while((pos=pos->next_sibling))
-      ++ret;
-   return ret;
-   }
+       {
+       tree_node *pos=it.node->first_child;
+       if(pos==0) return 0;
+       
+       unsigned int ret=1;
+//       while(pos!=it.node->last_child) {
+//               ++ret;
+//               pos=pos->next_sibling;
+//               }
+       while((pos=pos->next_sibling))
+               ++ret;
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 unsigned int tree<T, tree_node_allocator>::number_of_siblings(const 
iterator_base& it) const
-   {
-   tree_node *pos=it.node;
-   unsigned int ret=0;
-   // count forward
-   while(pos->next_sibling && 
-         pos->next_sibling!=head &&
-         pos->next_sibling!=feet) {
-      ++ret;
-      pos=pos->next_sibling;
-      }
-   // count backward
-   pos=it.node;
-   while(pos->prev_sibling && 
-         pos->prev_sibling!=head &&
-         pos->prev_sibling!=feet) {
-      ++ret;
-      pos=pos->prev_sibling;
-      }
-   
-   return ret;
-   }
+       {
+       tree_node *pos=it.node;
+       unsigned int ret=0;
+       // count forward
+       while(pos->next_sibling && 
+                       pos->next_sibling!=head &&
+                       pos->next_sibling!=feet) {
+               ++ret;
+               pos=pos->next_sibling;
+               }
+       // count backward
+       pos=it.node;
+       while(pos->prev_sibling && 
+                       pos->prev_sibling!=head &&
+                       pos->prev_sibling!=feet) {
+               ++ret;
+               pos=pos->prev_sibling;
+               }
+       
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::swap(sibling_iterator it)
-   {
-   tree_node *nxt=it.node->next_sibling;
-   if(nxt) {
-      if(it.node->prev_sibling)
-         it.node->prev_sibling->next_sibling=nxt;
-      else
-         it.node->parent->first_child=nxt;
-      nxt->prev_sibling=it.node->prev_sibling;
-      tree_node *nxtnxt=nxt->next_sibling;
-      if(nxtnxt)
-         nxtnxt->prev_sibling=it.node;
-      else
-         it.node->parent->last_child=it.node;
-      nxt->next_sibling=it.node;
-      it.node->prev_sibling=nxt;
-      it.node->next_sibling=nxtnxt;
-      }
-   }
+       {
+       tree_node *nxt=it.node->next_sibling;
+       if(nxt) {
+               if(it.node->prev_sibling)
+                       it.node->prev_sibling->next_sibling=nxt;
+               else
+                       it.node->parent->first_child=nxt;
+               nxt->prev_sibling=it.node->prev_sibling;
+               tree_node *nxtnxt=nxt->next_sibling;
+               if(nxtnxt)
+                       nxtnxt->prev_sibling=it.node;
+               else
+                       it.node->parent->last_child=it.node;
+               nxt->next_sibling=it.node;
+               it.node->prev_sibling=nxt;
+               it.node->next_sibling=nxtnxt;
+               }
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::swap(iterator one, iterator two)
-   {
-   // if one and two are adjacent siblings, use the sibling swap
-   if(one.node->next_sibling==two.node) swap(one);
-   else if(two.node->next_sibling==one.node) swap(two);
-   else {
-      tree_node *nxt1=one.node->next_sibling;
-      tree_node *nxt2=two.node->next_sibling;
-      tree_node *pre1=one.node->prev_sibling;
-      tree_node *pre2=two.node->prev_sibling;
-      tree_node *par1=one.node->parent;
-      tree_node *par2=two.node->parent;
-
-      // reconnect
-      one.node->parent=par2;
-      one.node->next_sibling=nxt2;
-      if(nxt2) nxt2->prev_sibling=one.node;
-      else     par2->last_child=one.node;
-      one.node->prev_sibling=pre2;
-      if(pre2) pre2->next_sibling=one.node;
-      else     par2->first_child=one.node;    
-
-      two.node->parent=par1;
-      two.node->next_sibling=nxt1;
-      if(nxt1) nxt1->prev_sibling=two.node;
-      else     par1->last_child=two.node;
-      two.node->prev_sibling=pre1;
-      if(pre1) pre1->next_sibling=two.node;
-      else     par1->first_child=two.node;
-      }
-   }
+       {
+       // if one and two are adjacent siblings, use the sibling swap
+       if(one.node->next_sibling==two.node) swap(one);
+       else if(two.node->next_sibling==one.node) swap(two);
+       else {
+               tree_node *nxt1=one.node->next_sibling;
+               tree_node *nxt2=two.node->next_sibling;
+               tree_node *pre1=one.node->prev_sibling;
+               tree_node *pre2=two.node->prev_sibling;
+               tree_node *par1=one.node->parent;
+               tree_node *par2=two.node->parent;
+
+               // reconnect
+               one.node->parent=par2;
+               one.node->next_sibling=nxt2;
+               if(nxt2) nxt2->prev_sibling=one.node;
+               else     par2->last_child=one.node;
+               one.node->prev_sibling=pre2;
+               if(pre2) pre2->next_sibling=one.node;
+               else     par2->first_child=one.node;    
+
+               two.node->parent=par1;
+               two.node->next_sibling=nxt1;
+               if(nxt1) nxt1->prev_sibling=two.node;
+               else     par1->last_child=two.node;
+               two.node->prev_sibling=pre1;
+               if(pre1) pre1->next_sibling=two.node;
+               else     par1->first_child=two.node;
+               }
+       }
 
 // template <class BinaryPredicate>
 // tree<T, tree_node_allocator>::iterator tree<T, 
tree_node_allocator>::find_subtree(
-//    sibling_iterator subfrom, sibling_iterator subto, iterator from, 
iterator to, 
-//    BinaryPredicate fun) const
-//    {
-//    assert(1==0); // this routine is not finished yet.
-//    while(from!=to) {
-//       if(fun(*subfrom, *from)) {
-//          
-//          }
-//       }
-//    return to;
-//    }
+//     sibling_iterator subfrom, sibling_iterator subto, iterator from, 
iterator to, 
+//     BinaryPredicate fun) const
+//     {
+//     assert(1==0); // this routine is not finished yet.
+//     while(from!=to) {
+//             if(fun(*subfrom, *from)) {
+//                     
+//                     }
+//             }
+//     return to;
+//     }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::is_in_subtree(const iterator_base& it, 
const iterator_base& begin, 
-                                                 const iterator_base& end) 
const
-   {
-   // FIXME: this should be optimised.
-   pre_order_iterator tmp=begin;
-   while(tmp!=end) {
-      if(tmp==it) return true;
-      ++tmp;
-      }
-   return false;
-   }
+                                                                               
                                                 const iterator_base& end) const
+       {
+       // FIXME: this should be optimised.
+       pre_order_iterator tmp=begin;
+       while(tmp!=end) {
+               if(tmp==it) return true;
+               ++tmp;
+               }
+       return false;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::is_valid(const iterator_base& it) const
-   {
-   if(it.node==0 || it.node==feet || it.node==head) return false;
-   else return true;
-   }
+       {
+       if(it.node==0 || it.node==feet || it.node==head) return false;
+       else return true;
+       }
 
 template <class T, class tree_node_allocator>
 unsigned int tree<T, tree_node_allocator>::index(sibling_iterator it) const
+       {
+       unsigned int ind=0;
+       if(it.node->parent==0) {
+               while(it.node->prev_sibling!=head) {
+                       it.node=it.node->prev_sibling;
+                       ++ind;
+                       }
+               }
+       else {
+               while(it.node->prev_sibling!=0) {
+                       it.node=it.node->prev_sibling;
+                       ++ind;
+                       }
+               }
+       return ind;
+       }
+
+template <class T, class tree_node_allocator>
+typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::sibling(const iterator_base& it, unsigned int num)
    {
-   unsigned int ind=0;
+   tree_node *tmp;
    if(it.node->parent==0) {
-      while(it.node->prev_sibling!=head) {
-         it.node=it.node->prev_sibling;
-         ++ind;
+      tmp=head->next_sibling;
+      while(num) {
+         tmp = tmp->next_sibling;
+         --num;
          }
       }
    else {
-      while(it.node->prev_sibling!=0) {
-         it.node=it.node->prev_sibling;
-         ++ind;
+      tmp=it.node->parent->first_child;
+      while(num) {
+         assert(tmp!=0);
+         tmp = tmp->next_sibling;
+         --num;
          }
       }
-   return ind;
+   return tmp;
    }
-
+ 
 
 template <class T, class tree_node_allocator>
-typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::child(const iterator_base& it, unsigned int num) const
-   {
-   tree_node *tmp=it.node->first_child;
-   while(num--) {
-      assert(tmp!=0);
-      tmp=tmp->next_sibling;
-      }
-   return tmp;
-   }
+typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::child(const iterator_base& it, unsigned int num) 
+       {
+       tree_node *tmp=it.node->first_child;
+       while(num--) {
+               assert(tmp!=0);
+               tmp=tmp->next_sibling;
+               }
+       return tmp;
+       }
 
 
 
@@ -1859,69 +1881,69 @@
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::iterator_base::iterator_base()
-   : node(0), skip_current_children_(false)
-   {
-   }
+       : node(0), skip_current_children_(false)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::iterator_base::iterator_base(tree_node *tn)
-   : node(tn), skip_current_children_(false)
-   {
-   }
+       : node(tn), skip_current_children_(false)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 T& tree<T, tree_node_allocator>::iterator_base::operator*() const
-   {
-   return node->data;
-   }
+       {
+       return node->data;
+       }
 
 template <class T, class tree_node_allocator>
 T* tree<T, tree_node_allocator>::iterator_base::operator->() const
-   {
-   return &(node->data);
-   }
+       {
+       return &(node->data);
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::post_order_iterator::operator!=(const 
post_order_iterator& other) const
-   {
-   if(other.node!=this->node) return true;
-   else return false;
-   }
+       {
+       if(other.node!=this->node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::post_order_iterator::operator==(const 
post_order_iterator& other) const
-   {
-   if(other.node==this->node) return true;
-   else return false;
-   }
+       {
+       if(other.node==this->node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::pre_order_iterator::operator!=(const 
pre_order_iterator& other) const
-   {
-   if(other.node!=this->node) return true;
-   else return false;
-   }
+       {
+       if(other.node!=this->node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::pre_order_iterator::operator==(const 
pre_order_iterator& other) const
-   {
-   if(other.node==this->node) return true;
-   else return false;
-   }
+       {
+       if(other.node==this->node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::sibling_iterator::operator!=(const 
sibling_iterator& other) const
-   {
-   if(other.node!=this->node) return true;
-   else return false;
-   }
+       {
+       if(other.node!=this->node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::sibling_iterator::operator==(const 
sibling_iterator& other) const
-   {
-   if(other.node==this->node) return true;
-   else return false;
-   }
+       {
+       if(other.node==this->node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::leaf_iterator::operator!=(const 
leaf_iterator& other) const
@@ -1933,48 +1955,54 @@
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::leaf_iterator::operator==(const 
leaf_iterator& other) const
    {
-   if(other.node==this->node && other.top==this->top) return true;
+   if(other.node==this->node && other.top_node==this->top_node) return true;
    else return false;
    }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::iterator_base::begin() const
-   {
-   if(node->first_child==0) 
-      return end();
+       {
+       if(node->first_child==0) 
+               return end();
 
-   sibling_iterator ret(node->first_child);
-   ret.parent_=this->node;
-   return ret;
-   }
+       sibling_iterator ret(node->first_child);
+       ret.parent_=this->node;
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::iterator_base::end() const
-   {
-   sibling_iterator ret(0);
-   ret.parent_=node;
-   return ret;
-   }
+       {
+       sibling_iterator ret(0);
+       ret.parent_=node;
+       return ret;
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::iterator_base::skip_children()
+       {
+       skip_current_children_=true;
+       }
+
+template <class T, class tree_node_allocator>
+void tree<T, tree_node_allocator>::iterator_base::skip_children(bool skip)
    {
-   skip_current_children_=true;
+   skip_current_children_=skip;
    }
 
 template <class T, class tree_node_allocator>
 unsigned int tree<T, tree_node_allocator>::iterator_base::number_of_children() 
const
-   {
-   tree_node *pos=node->first_child;
-   if(pos==0) return 0;
-   
-   unsigned int ret=1;
-   while(pos!=node->last_child) {
-      ++ret;
-      pos=pos->next_sibling;
-      }
-   return ret;
-   }
+       {
+       tree_node *pos=node->first_child;
+       if(pos==0) return 0;
+       
+       unsigned int ret=1;
+       while(pos!=node->last_child) {
+               ++ret;
+               pos=pos->next_sibling;
+               }
+       return ret;
+       }
 
 
 
@@ -1982,82 +2010,82 @@
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::pre_order_iterator::pre_order_iterator() 
-   : iterator_base(0)
-   {
-   }
+       : iterator_base(0)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::pre_order_iterator::pre_order_iterator(tree_node 
*tn)
-   : iterator_base(tn)
-   {
-   }
+       : iterator_base(tn)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::pre_order_iterator::pre_order_iterator(const 
iterator_base &other)
-   : iterator_base(other.node)
-   {
-   }
+       : iterator_base(other.node)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::pre_order_iterator::pre_order_iterator(const 
sibling_iterator& other)
-   : iterator_base(other.node)
-   {
-   if(this->node==0) {
-      if(other.range_last()!=0)
-         this->node=other.range_last();
-      else 
-         this->node=other.parent_;
-      this->skip_children();
-      ++(*this);
-      }
-   }
+       : iterator_base(other.node)
+       {
+       if(this->node==0) {
+               if(other.range_last()!=0)
+                       this->node=other.range_last();
+               else 
+                       this->node=other.parent_;
+               this->skip_children();
+               ++(*this);
+               }
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::pre_order_iterator& tree<T, 
tree_node_allocator>::pre_order_iterator::operator++()
-   {
-   assert(this->node!=0);
-   if(!this->skip_current_children_ && this->node->first_child != 0) {
-      this->node=this->node->first_child;
-      }
-   else {
-      this->skip_current_children_=false;
-      while(this->node->next_sibling==0) {
-         this->node=this->node->parent;
-         if(this->node==0)
-            return *this;
-         }
-      this->node=this->node->next_sibling;
-      }
-   return *this;
-   }
+       {
+       assert(this->node!=0);
+       if(!this->skip_current_children_ && this->node->first_child != 0) {
+               this->node=this->node->first_child;
+               }
+       else {
+               this->skip_current_children_=false;
+               while(this->node->next_sibling==0) {
+                       this->node=this->node->parent;
+                       if(this->node==0)
+                               return *this;
+                       }
+               this->node=this->node->next_sibling;
+               }
+       return *this;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::pre_order_iterator& tree<T, 
tree_node_allocator>::pre_order_iterator::operator--()
-   {
-   assert(this->node!=0);
-   if(this->node->prev_sibling) {
-      this->node=this->node->prev_sibling;
-      while(this->node->last_child)
-         this->node=this->node->last_child;
-      }
-   else {
-      this->node=this->node->parent;
-      if(this->node==0)
-         return *this;
-      }
-   return *this;
+       {
+       assert(this->node!=0);
+       if(this->node->prev_sibling) {
+               this->node=this->node->prev_sibling;
+               while(this->node->last_child)
+                       this->node=this->node->last_child;
+               }
+       else {
+               this->node=this->node->parent;
+               if(this->node==0)
+                       return *this;
+               }
+       return *this;
 }
 
 template <class T, class tree_node_allocator>
-typename tree<T, tree_node_allocator>::pre_order_iterator tree<T, 
tree_node_allocator>::pre_order_iterator::operator++(int n)
-   {
-   pre_order_iterator copy = *this;
-   ++(*this);
-   return copy;
-   }
+typename tree<T, tree_node_allocator>::pre_order_iterator tree<T, 
tree_node_allocator>::pre_order_iterator::operator++(int)
+       {
+       pre_order_iterator copy = *this;
+       ++(*this);
+       return copy;
+       }
 
 template <class T, class tree_node_allocator>
-typename tree<T, tree_node_allocator>::pre_order_iterator tree<T, 
tree_node_allocator>::pre_order_iterator::operator--(int n)
+typename tree<T, tree_node_allocator>::pre_order_iterator tree<T, 
tree_node_allocator>::pre_order_iterator::operator--(int)
 {
   pre_order_iterator copy = *this;
   --(*this);
@@ -2066,23 +2094,23 @@
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::pre_order_iterator& tree<T, 
tree_node_allocator>::pre_order_iterator::operator+=(unsigned int num)
-   {
-   while(num>0) {
-      ++(*this);
-      --num;
-      }
-   return (*this);
-   }
+       {
+       while(num>0) {
+               ++(*this);
+               --num;
+               }
+       return (*this);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::pre_order_iterator& tree<T, 
tree_node_allocator>::pre_order_iterator::operator-=(unsigned int num)
-   {
-   while(num>0) {
-      --(*this);
-      --num;
-      }
-   return (*this);
-   }
+       {
+       while(num>0) {
+               --(*this);
+               --num;
+               }
+       return (*this);
+       }
 
 
 
@@ -2090,191 +2118,191 @@
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::post_order_iterator::post_order_iterator() 
-   : iterator_base(0)
-   {
-   }
+       : iterator_base(0)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, 
tree_node_allocator>::post_order_iterator::post_order_iterator(tree_node *tn)
-   : iterator_base(tn)
-   {
-   }
+       : iterator_base(tn)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::post_order_iterator::post_order_iterator(const 
iterator_base &other)
-   : iterator_base(other.node)
-   {
-   }
+       : iterator_base(other.node)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::post_order_iterator::post_order_iterator(const 
sibling_iterator& other)
-   : iterator_base(other.node)
-   {
-   if(this->node==0) {
-      if(other.range_last()!=0)
-         this->node=other.range_last();
-      else 
-         this->node=other.parent_;
-      this->skip_children();
-      ++(*this);
-      }
-   }
+       : iterator_base(other.node)
+       {
+       if(this->node==0) {
+               if(other.range_last()!=0)
+                       this->node=other.range_last();
+               else 
+                       this->node=other.parent_;
+               this->skip_children();
+               ++(*this);
+               }
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::post_order_iterator& tree<T, 
tree_node_allocator>::post_order_iterator::operator++()
-   {
-   assert(this->node!=0);
-   if(this->node->next_sibling==0) {
-      this->node=this->node->parent;
-      this->skip_current_children_=false;
-      }
-   else {
-      this->node=this->node->next_sibling;
-      if(this->skip_current_children_) {
-         this->skip_current_children_=false;
-         }
-      else {
-         while(this->node->first_child)
-            this->node=this->node->first_child;
-         }
-      }
-   return *this;
-   }
+       {
+       assert(this->node!=0);
+       if(this->node->next_sibling==0) {
+               this->node=this->node->parent;
+               this->skip_current_children_=false;
+               }
+       else {
+               this->node=this->node->next_sibling;
+               if(this->skip_current_children_) {
+                       this->skip_current_children_=false;
+                       }
+               else {
+                       while(this->node->first_child)
+                               this->node=this->node->first_child;
+                       }
+               }
+       return *this;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::post_order_iterator& tree<T, 
tree_node_allocator>::post_order_iterator::operator--()
-   {
-   assert(this->node!=0);
-   if(this->skip_current_children_ || this->node->last_child==0) {
-      this->skip_current_children_=false;
-      while(this->node->prev_sibling==0)
-         this->node=this->node->parent;
-      this->node=this->node->prev_sibling;
-      }
-   else {
-      this->node=this->node->last_child;
-      }
-   return *this;
-   }
+       {
+       assert(this->node!=0);
+       if(this->skip_current_children_ || this->node->last_child==0) {
+               this->skip_current_children_=false;
+               while(this->node->prev_sibling==0)
+                       this->node=this->node->parent;
+               this->node=this->node->prev_sibling;
+               }
+       else {
+               this->node=this->node->last_child;
+               }
+       return *this;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::post_order_iterator tree<T, 
tree_node_allocator>::post_order_iterator::operator++(int)
-   {
-   post_order_iterator copy = *this;
-   ++(*this);
-   return copy;
-   }
+       {
+       post_order_iterator copy = *this;
+       ++(*this);
+       return copy;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::post_order_iterator tree<T, 
tree_node_allocator>::post_order_iterator::operator--(int)
-   {
-   post_order_iterator copy = *this;
-   --(*this);
-   return copy;
-   }
+       {
+       post_order_iterator copy = *this;
+       --(*this);
+       return copy;
+       }
 
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::post_order_iterator& tree<T, 
tree_node_allocator>::post_order_iterator::operator+=(unsigned int num)
-   {
-   while(num>0) {
-      ++(*this);
-      --num;
-      }
-   return (*this);
-   }
+       {
+       while(num>0) {
+               ++(*this);
+               --num;
+               }
+       return (*this);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::post_order_iterator& tree<T, 
tree_node_allocator>::post_order_iterator::operator-=(unsigned int num)
-   {
-   while(num>0) {
-      --(*this);
-      --num;
-      }
-   return (*this);
-   }
+       {
+       while(num>0) {
+               --(*this);
+               --num;
+               }
+       return (*this);
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::post_order_iterator::descend_all()
-   {
-   assert(this->node!=0);
-   while(this->node->first_child)
-      this->node=this->node->first_child;
-   }
+       {
+       assert(this->node!=0);
+       while(this->node->first_child)
+               this->node=this->node->first_child;
+       }
 
 
 // Breadth-first iterator
 
 template <class T, class tree_node_allocator>
 tree<T, 
tree_node_allocator>::breadth_first_queued_iterator::breadth_first_queued_iterator()
-   : iterator_base()
-   {
-   }
+       : iterator_base()
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, 
tree_node_allocator>::breadth_first_queued_iterator::breadth_first_queued_iterator(tree_node
 *tn)
-   : iterator_base(tn)
-   {
-   traversal_queue.push(tn);
-   }
+       : iterator_base(tn)
+       {
+       traversal_queue.push(tn);
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, 
tree_node_allocator>::breadth_first_queued_iterator::breadth_first_queued_iterator(const
 iterator_base& other)
-   : iterator_base(other.node)
-   {
-   traversal_queue.push(other.node);
-   }
+       : iterator_base(other.node)
+       {
+       traversal_queue.push(other.node);
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, 
tree_node_allocator>::breadth_first_queued_iterator::operator!=(const 
breadth_first_queued_iterator& other) const
-   {
-   if(other.node!=this->node) return true;
-   else return false;
-   }
+       {
+       if(other.node!=this->node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, 
tree_node_allocator>::breadth_first_queued_iterator::operator==(const 
breadth_first_queued_iterator& other) const
-   {
-   if(other.node==this->node) return true;
-   else return false;
-   }
+       {
+       if(other.node==this->node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::breadth_first_queued_iterator& tree<T, 
tree_node_allocator>::breadth_first_queued_iterator::operator++()
-   {
-   assert(this->node!=0);
+       {
+       assert(this->node!=0);
 
-   // Add child nodes and pop current node
-   sibling_iterator sib=this->begin();
-   while(sib!=this->end()) {
-      traversal_queue.push(sib.node);
-      ++sib;
-      }
-   traversal_queue.pop();
-   if(traversal_queue.size()>0)
-      this->node=traversal_queue.front();
-   else 
-      this->node=0;
-   return (*this);
-   }
+       // Add child nodes and pop current node
+       sibling_iterator sib=this->begin();
+       while(sib!=this->end()) {
+               traversal_queue.push(sib.node);
+               ++sib;
+               }
+       traversal_queue.pop();
+       if(traversal_queue.size()>0)
+               this->node=traversal_queue.front();
+       else 
+               this->node=0;
+       return (*this);
+       }
 
 template <class T, class tree_node_allocator>
-typename tree<T, tree_node_allocator>::breadth_first_queued_iterator tree<T, 
tree_node_allocator>::breadth_first_queued_iterator::operator++(int n)
-   {
-   breadth_first_queued_iterator copy = *this;
-   ++(*this);
-   return copy;
-   }
+typename tree<T, tree_node_allocator>::breadth_first_queued_iterator tree<T, 
tree_node_allocator>::breadth_first_queued_iterator::operator++(int)
+       {
+       breadth_first_queued_iterator copy = *this;
+       ++(*this);
+       return copy;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::breadth_first_queued_iterator& tree<T, 
tree_node_allocator>::breadth_first_queued_iterator::operator+=(unsigned int 
num)
-   {
-   while(num>0) {
-      ++(*this);
-      --num;
-      }
-   return (*this);
-   }
+       {
+       while(num>0) {
+               ++(*this);
+               --num;
+               }
+       return (*this);
+       }
 
 
 
@@ -2282,300 +2310,292 @@
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::fixed_depth_iterator::fixed_depth_iterator()
-   : iterator_base()
-   {
-   set_first_parent_();
-   }
+       : iterator_base()
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, 
tree_node_allocator>::fixed_depth_iterator::fixed_depth_iterator(tree_node *tn)
-   : iterator_base(tn)
-   {
-   set_first_parent_();
-   }
+       : iterator_base(tn), top_node(0)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::fixed_depth_iterator::fixed_depth_iterator(const 
iterator_base& other)
-   : iterator_base(other.node)
-   {
-   set_first_parent_();
-   }
+       : iterator_base(other.node), top_node(0)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::fixed_depth_iterator::fixed_depth_iterator(const 
sibling_iterator& other)
-   : iterator_base(other.node), first_parent_(other.parent_)
-   {
-   find_leftmost_parent_();
-   }
+       : iterator_base(other.node), top_node(0)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::fixed_depth_iterator::fixed_depth_iterator(const 
fixed_depth_iterator& other)
-   : iterator_base(other.node), first_parent_(other.first_parent_)
-   {
-   }
+       : iterator_base(other.node), top_node(other.top_node)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::fixed_depth_iterator::operator==(const 
fixed_depth_iterator& other) const
-   {
-   if(other.node==this->node && other.first_parent_==first_parent_) return 
true;
-   else return false;
-   }
+       {
+       if(other.node==this->node && other.top_node==top_node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 bool tree<T, tree_node_allocator>::fixed_depth_iterator::operator!=(const 
fixed_depth_iterator& other) const
-   {
-   if(other.node!=this->node || other.first_parent_!=first_parent_) return 
true;
-   else return false;
-   }
-
-template <class T, class tree_node_allocator>
-void tree<T, tree_node_allocator>::fixed_depth_iterator::set_first_parent_()
-   {
-   return; // FIXME: we do not use first_parent_ yet, and it actually needs 
some serious reworking if
-           // it is ever to work at the 'head' level.
-   first_parent_=0;
-   if(this->node==0) return;
-   if(this->node->parent!=0)
-      first_parent_=this->node->parent;
-   if(first_parent_)
-      find_leftmost_parent_();
-   }
-
-template <class T, class tree_node_allocator>
-void tree<T, 
tree_node_allocator>::fixed_depth_iterator::find_leftmost_parent_()
-   {
-   return; // FIXME: see 'set_first_parent()'
-   tree_node *tmppar=first_parent_;
-   while(tmppar->prev_sibling) {
-      tmppar=tmppar->prev_sibling;
-      if(tmppar->first_child)
-         first_parent_=tmppar;
-      }
-   }
+       {
+       if(other.node!=this->node || other.top_node!=top_node) return true;
+       else return false;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::fixed_depth_iterator& tree<T, 
tree_node_allocator>::fixed_depth_iterator::operator++()
-   {
-   assert(this->node!=0);
-
-   if(this->node->next_sibling) {
-      this->node=this->node->next_sibling;
-      }
-   else { 
-      int relative_depth=0;
-      upper:
-      do {
-         this->node=this->node->parent;
-         if(this->node==0) return *this;
-         --relative_depth;
-         } while(this->node->next_sibling==0);
-      lower:
-      this->node=this->node->next_sibling;
-      while(this->node->first_child==0) {
-         if(this->node->next_sibling==0)
-            goto upper;
-         this->node=this->node->next_sibling;
-         if(this->node==0) return *this;
-         }
-      while(relative_depth<0 && this->node->first_child!=0) {
-         this->node=this->node->first_child;
-         ++relative_depth;
-         }
-      if(relative_depth<0) {
-         if(this->node->next_sibling==0) goto upper;
-         else                          goto lower;
-         }
-      }
-   return *this;
-
-// if(this->node->next_sibling!=0) {
-//    this->node=this->node->next_sibling;
-//    assert(this->node!=0);
-//    if(this->node->parent==0 && this->node->next_sibling==0) // feet element
-//       this->node=0;
-//    }
-// else {
-//    tree_node *par=this->node->parent;
-//    do {
-//       par=par->next_sibling;
-//       if(par==0) { // FIXME: need to keep track of this!
-//          this->node=0;
-//          return *this;
-//          }
-//       } while(par->first_child==0);
-//    this->node=par->first_child;
-//    }
-   return *this;
-   }
+       {
+       assert(this->node!=0);
+
+       if(this->node->next_sibling) {
+               this->node=this->node->next_sibling;
+               }
+       else { 
+               int relative_depth=0;
+          upper:
+               do {
+                       if(this->node==this->top_node) {
+                               this->node=0; // FIXME: return a proper 
fixed_depth end iterator once implemented
+                               return *this;
+                               }
+                       this->node=this->node->parent;
+                       if(this->node==0) return *this;
+                       --relative_depth;
+                       } while(this->node->next_sibling==0);
+          lower:
+               this->node=this->node->next_sibling;
+               while(this->node->first_child==0) {
+                       if(this->node->next_sibling==0)
+                               goto upper;
+                       this->node=this->node->next_sibling;
+                       if(this->node==0) return *this;
+                       }
+               while(relative_depth<0 && this->node->first_child!=0) {
+                       this->node=this->node->first_child;
+                       ++relative_depth;
+                       }
+               if(relative_depth<0) {
+                       if(this->node->next_sibling==0) goto upper;
+                       else                          goto lower;
+                       }
+               }
+       return *this;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::fixed_depth_iterator& tree<T, 
tree_node_allocator>::fixed_depth_iterator::operator--()
-   {
-   assert(this->node!=0);
-   if(this->node->prev_sibling!=0) {
-      this->node=this->node->prev_sibling;
-      assert(this->node!=0);
-      if(this->node->parent==0 && this->node->prev_sibling==0) // head element
-         this->node=0;
-      }
-   else {
-      tree_node *par=this->node->parent;
-      do {
-         par=par->prev_sibling;
-         if(par==0) { // FIXME: need to keep track of this!
-            this->node=0;
-            return *this;
-            }
-         } while(par->last_child==0);
-      this->node=par->last_child;
-      }
-   return *this;
-}
+       {
+       assert(this->node!=0);
+
+       if(this->node->prev_sibling) {
+               this->node=this->node->prev_sibling;
+               }
+       else { 
+               int relative_depth=0;
+          upper:
+               do {
+                       if(this->node==this->top_node) {
+                               this->node=0;
+                               return *this;
+                               }
+                       this->node=this->node->parent;
+                       if(this->node==0) return *this;
+                       --relative_depth;
+                       } while(this->node->prev_sibling==0);
+          lower:
+               this->node=this->node->prev_sibling;
+               while(this->node->last_child==0) {
+                       if(this->node->prev_sibling==0)
+                               goto upper;
+                       this->node=this->node->prev_sibling;
+                       if(this->node==0) return *this;
+                       }
+               while(relative_depth<0 && this->node->last_child!=0) {
+                       this->node=this->node->last_child;
+                       ++relative_depth;
+                       }
+               if(relative_depth<0) {
+                       if(this->node->prev_sibling==0) goto upper;
+                       else                            goto lower;
+                       }
+               }
+       return *this;
+
+//
+//
+//     assert(this->node!=0);
+//     if(this->node->prev_sibling!=0) {
+//             this->node=this->node->prev_sibling;
+//             assert(this->node!=0);
+//             if(this->node->parent==0 && this->node->prev_sibling==0) // 
head element
+//                     this->node=0;
+//             }
+//     else {
+//             tree_node *par=this->node->parent;
+//             do {
+//                     par=par->prev_sibling;
+//                     if(par==0) { // FIXME: need to keep track of this!
+//                             this->node=0;
+//                             return *this;
+//                             }
+//                     } while(par->last_child==0);
+//             this->node=par->last_child;
+//             }
+//     return *this;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::fixed_depth_iterator tree<T, 
tree_node_allocator>::fixed_depth_iterator::operator++(int)
-   {
-   fixed_depth_iterator copy = *this;
-   ++(*this);
-   return copy;
-   }
+       {
+       fixed_depth_iterator copy = *this;
+       ++(*this);
+       return copy;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::fixed_depth_iterator tree<T, 
tree_node_allocator>::fixed_depth_iterator::operator--(int)
-{
-  fixed_depth_iterator copy = *this;
-  --(*this);
-  return copy;
-}
+   {
+       fixed_depth_iterator copy = *this;
+       --(*this);
+       return copy;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::fixed_depth_iterator& tree<T, 
tree_node_allocator>::fixed_depth_iterator::operator-=(unsigned int num)
-   {
-   while(num>0) {
-      --(*this);
-      --(num);
-      }
-   return (*this);
-   }
+       {
+       while(num>0) {
+               --(*this);
+               --(num);
+               }
+       return (*this);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::fixed_depth_iterator& tree<T, 
tree_node_allocator>::fixed_depth_iterator::operator+=(unsigned int num)
-   {
-   while(num>0) {
-      ++(*this);
-      --(num);
-      }
-   return *this;
-   }
-
-// FIXME: add the other members of fixed_depth_iterator.
+       {
+       while(num>0) {
+               ++(*this);
+               --(num);
+               }
+       return *this;
+       }
 
 
 // Sibling iterator
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::sibling_iterator::sibling_iterator() 
-   : iterator_base()
-   {
-   set_parent_();
-   }
+       : iterator_base()
+       {
+       set_parent_();
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::sibling_iterator::sibling_iterator(tree_node *tn)
-   : iterator_base(tn)
-   {
-   set_parent_();
-   }
+       : iterator_base(tn)
+       {
+       set_parent_();
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::sibling_iterator::sibling_iterator(const 
iterator_base& other)
-   : iterator_base(other.node)
-   {
-   set_parent_();
-   }
+       : iterator_base(other.node)
+       {
+       set_parent_();
+       }
 
 template <class T, class tree_node_allocator>
 tree<T, tree_node_allocator>::sibling_iterator::sibling_iterator(const 
sibling_iterator& other)
-   : iterator_base(other), parent_(other.parent_)
-   {
-   }
+       : iterator_base(other), parent_(other.parent_)
+       {
+       }
 
 template <class T, class tree_node_allocator>
 void tree<T, tree_node_allocator>::sibling_iterator::set_parent_()
-   {
-   parent_=0;
-   if(this->node==0) return;
-   if(this->node->parent!=0)
-      parent_=this->node->parent;
-   }
+       {
+       parent_=0;
+       if(this->node==0) return;
+       if(this->node->parent!=0)
+               parent_=this->node->parent;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator& tree<T, 
tree_node_allocator>::sibling_iterator::operator++()
-   {
-   if(this->node)
-      this->node=this->node->next_sibling;
-   return *this;
-   }
+       {
+       if(this->node)
+               this->node=this->node->next_sibling;
+       return *this;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator& tree<T, 
tree_node_allocator>::sibling_iterator::operator--()
-   {
-   if(this->node) this->node=this->node->prev_sibling;
-   else {
-      assert(parent_);
-      this->node=parent_->last_child;
-      }
-   return *this;
+       {
+       if(this->node) this->node=this->node->prev_sibling;
+       else {
+               assert(parent_);
+               this->node=parent_->last_child;
+               }
+       return *this;
 }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::sibling_iterator::operator++(int)
-   {
-   sibling_iterator copy = *this;
-   ++(*this);
-   return copy;
-   }
+       {
+       sibling_iterator copy = *this;
+       ++(*this);
+       return copy;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator tree<T, 
tree_node_allocator>::sibling_iterator::operator--(int)
-   {
-   sibling_iterator copy = *this;
-   --(*this);
-   return copy;
-   }
+       {
+       sibling_iterator copy = *this;
+       --(*this);
+       return copy;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator& tree<T, 
tree_node_allocator>::sibling_iterator::operator+=(unsigned int num)
-   {
-   while(num>0) {
-      ++(*this);
-      --num;
-      }
-   return (*this);
-   }
+       {
+       while(num>0) {
+               ++(*this);
+               --num;
+               }
+       return (*this);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::sibling_iterator& tree<T, 
tree_node_allocator>::sibling_iterator::operator-=(unsigned int num)
-   {
-   while(num>0) {
-      --(*this);
-      --num;
-      }
-   return (*this);
-   }
+       {
+       while(num>0) {
+               --(*this);
+               --num;
+               }
+       return (*this);
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::tree_node *tree<T, 
tree_node_allocator>::sibling_iterator::range_first() const
-   {
-   tree_node *tmp=parent_->first_child;
-   return tmp;
-   }
+       {
+       tree_node *tmp=parent_->first_child;
+       return tmp;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::tree_node *tree<T, 
tree_node_allocator>::sibling_iterator::range_last() const
-   {
-   return parent_->last_child;
-   }
+       {
+       return parent_->last_child;
+       }
 
 // Leaf iterator
 
@@ -2613,32 +2633,38 @@
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::leaf_iterator& tree<T, 
tree_node_allocator>::leaf_iterator::operator++()
    {
-   assert(this->node!=0);
-   while(this->node->next_sibling==0) {
-      if (this->node->parent==0) return *this;
-      this->node=this->node->parent;
-      if (top_node != 0 && this->node==top_node) return *this;
-      }
-   this->node=this->node->next_sibling;
-   while(this->node->first_child)
-      this->node=this->node->first_child;
-   return *this;
+       assert(this->node!=0);
+       if(this->node->first_child!=0) { // current node is no longer leaf 
(children got added)
+                while(this->node->first_child) 
+                         this->node=this->node->first_child;
+                }
+       else {
+                while(this->node->next_sibling==0) { 
+                         if (this->node->parent==0) return *this;
+                         this->node=this->node->parent;
+                         if (top_node != 0 && this->node==top_node) return 
*this;
+                         }
+                this->node=this->node->next_sibling;
+                while(this->node->first_child)
+                         this->node=this->node->first_child;
+                }
+       return *this;
    }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::leaf_iterator& tree<T, 
tree_node_allocator>::leaf_iterator::operator--()
    {
-   assert(this->node!=0);
-   while (this->node->prev_sibling==0) {
-      if (this->node->parent==0) return *this;
-      this->node=this->node->parent;
-      if (top_node !=0 && this->node==top_node) return *this; 
-      }
-   this->node=this->node->prev_sibling;
-   while(this->node->last_child)
-      this->node=this->node->last_child;
-   return *this;
-   }
+       assert(this->node!=0);
+       while (this->node->prev_sibling==0) {
+               if (this->node->parent==0) return *this;
+               this->node=this->node->parent;
+               if (top_node !=0 && this->node==top_node) return *this; 
+               }
+       this->node=this->node->prev_sibling;
+       while(this->node->last_child)
+               this->node=this->node->last_child;
+       return *this;
+       }
 
 template <class T, class tree_node_allocator>
 typename tree<T, tree_node_allocator>::leaf_iterator tree<T, 
tree_node_allocator>::leaf_iterator::operator++(int)


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