diff -r c3244a26adb1 -r e37cca875667 src/lemon/xy.h
--- a/src/lemon/xy.h	Sat May 14 17:34:31 2005 +0000
+++ b/src/lemon/xy.h	Sat May 14 17:37:33 2005 +0000
@@ -18,6 +18,7 @@
 #define LEMON_XY_H
 
 #include <iostream>
+#include <lemon/utility.h>
 
 ///\ingroup misc
 ///\file
@@ -350,12 +351,14 @@
   template<class M>
   class XMap 
   {
-    M &_map;
+    typename SmartReference<M>::Type _map;
   public:
+    typedef True NeedCopy;
+
     typedef typename M::Value::Value Value;
     typedef typename M::Key Key;
     ///\e
-    XMap(M &map) : _map(map) {}
+    XMap(typename SmartParameter<M>::Type map) : _map(map) {}
     Value operator[](Key k) const {return _map[k].x;}
     void set(Key k,Value v) {_map.set(k,typename M::Value(v,_map[k].y));}
   };
@@ -372,6 +375,12 @@
     return XMap<M>(m);
   }
 
+  template<class M> 
+  inline XMap<M> xMap(const M &m) 
+  {
+    return XMap<M>(m);
+  }
+
   ///Constant (read only) version of \ref XMap
 
   ///\ingroup maps
@@ -379,8 +388,10 @@
   template<class M>
   class ConstXMap 
   {
-    const M &_map;
+    typename SmartConstReference<M>::Type _map;
   public:
+    typedef True NeedCopy;
+
     typedef typename M::Value::Value Value;
     typedef typename M::Key Key;
     ///\e
@@ -407,12 +418,14 @@
   template<class M>
   class YMap 
   {
-    M &_map;
+    typename SmartReference<M>::Type _map;
   public:
+    typedef True NeedCopy;
+
     typedef typename M::Value::Value Value;
     typedef typename M::Key Key;
     ///\e
-    YMap(M &map) : _map(map) {}
+    YMap(typename SmartParameter<M>::Type map) : _map(map) {}
     Value operator[](Key k) const {return _map[k].y;}
     void set(Key k,Value v) {_map.set(k,typename M::Value(_map[k].x,v));}
   };
@@ -429,6 +442,12 @@
     return YMap<M>(m);
   }
 
+  template<class M> 
+  inline YMap<M> yMap(const M &m) 
+  {
+    return YMap<M>(m);
+  }
+
   ///Constant (read only) version of \ref YMap
 
   ///\ingroup maps
@@ -436,8 +455,10 @@
   template<class M>
   class ConstYMap 
   {
-    const M &_map;
+    typename SmartConstReference<M>::Type _map;
   public:
+    typedef True NeedCopy;
+
     typedef typename M::Value::Value Value;
     typedef typename M::Key Key;
     ///\e
@@ -466,8 +487,10 @@
   template<class M>
   class NormSquareMap 
   {
-    const M &_map;
+    typename SmartConstReference<M>::Type _map;
   public:
+    typedef True NeedCopy;
+
     typedef typename M::Value::Value Value;
     typedef typename M::Key Key;
     ///\e