diff --git a/example/composite_keys.cpp b/example/composite_keys.cpp
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+++ b/example/composite_keys.cpp
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+/* Boost.MultiIndex example of composite keys.
+ *
+ * Copyright 2003-2008 Joaquin M Lopez Munoz.
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * See http://www.boost.org/libs/multi_index for library home page.
+ */
+
+#if !defined(NDEBUG)
+#define BOOST_MULTI_INDEX_ENABLE_INVARIANT_CHECKING
+#define BOOST_MULTI_INDEX_ENABLE_SAFE_MODE
+#endif
+
+#include <boost/call_traits.hpp>
+#include <boost/multi_index_container.hpp>
+#include <boost/multi_index/composite_key.hpp>
+#include <boost/multi_index/member.hpp>
+#include <boost/multi_index/ordered_index.hpp>
+#include <boost/next_prior.hpp>
+#include <boost/tokenizer.hpp>
+#include <functional>
+#include <iostream>
+#include <iterator>
+#include <map>
+#include <string>
+
+using namespace boost::multi_index;
+
+/* A file record maintains some info on name and size as well
+ * as a pointer to the directory it belongs (null meaning the root
+ * directory.)
+ */
+
+struct file_entry
+{
+  file_entry(
+    std::string name_,unsigned size_,bool is_dir_,const file_entry* dir_):
+    name(name_),size(size_),is_dir(is_dir_),dir(dir_)
+  {}
+
+  std::string       name;
+  unsigned          size;
+  bool              is_dir;
+  const file_entry* dir;
+
+  friend std::ostream& operator<<(std::ostream& os,const file_entry& f)
+  {
+    os<<f.name<<"\t"<<f.size;
+    if(f.is_dir)os<<"\t <dir>";
+    return os;
+  }
+};
+
+/* A file system is just a multi_index_container of entries with indices on
+ * file and size. These indices are firstly ordered by directory, as commands
+ * work on a current directory basis. Composite keys are just fine to model
+ * this.
+ * NB: The use of derivation here instead of simple typedef is explained in
+ * Compiler specifics: type hiding.
+ */
+
+struct name_key:composite_key<
+  file_entry,
+  BOOST_MULTI_INDEX_MEMBER(file_entry,const file_entry*,dir),
+  BOOST_MULTI_INDEX_MEMBER(file_entry,std::string,name)
+>{};
+
+struct size_key:composite_key<
+  file_entry,
+  BOOST_MULTI_INDEX_MEMBER(file_entry,const file_entry* const,dir),
+  BOOST_MULTI_INDEX_MEMBER(file_entry,unsigned,size)
+>{};
+
+/* see Compiler specifics: composite_key in compilers without partial
+ * template specialization, for info on composite_key_result_less
+ */
+
+typedef multi_index_container<
+  file_entry,
+  indexed_by<
+    /* primary index sorted by name (inside the same directory) */
+    ordered_unique<name_key>,
+    /* secondary index sorted by size (inside the same directory) */
+    ordered_non_unique<size_key>
+  >
+> file_system;
+
+/* typedef's of the two indices of file_system */
+
+typedef nth_index<file_system,0>::type file_system_by_name;
+typedef nth_index<file_system,1>::type file_system_by_size;
+
+/* We build a rudimentary file system simulation out of some global
+ * info and a map of commands provided to the user.
+ */
+
+static file_system fs;                 /* the one and only file system */
+static file_system_by_name& fs_by_name=fs;         /* name index to fs */
+static file_system_by_size& fs_by_size=get<1>(fs); /* size index to fs */
+static const file_entry* current_dir=0;            /* root directory   */
+
+/* command framework */
+
+/* A command provides an execute memfun fed with the corresponding params
+ * (first param is stripped off as it serves to identify the command
+ * currently being used.)
+ */
+
+typedef boost::tokenizer<boost::char_separator<char> > command_tokenizer;
+
+class command
+{
+public:
+  virtual ~command(){}
+  virtual void execute(
+    command_tokenizer::iterator tok1,command_tokenizer::iterator tok2)=0;
+};
+
+/* available commands */
+
+/* cd: syntax cd [.|..|<directory>] */
+
+class command_cd:public command
+{
+public:
+  virtual void execute(
+    command_tokenizer::iterator tok1,command_tokenizer::iterator tok2)
+  {
+    if(tok1==tok2)return;
+    std::string dir=*tok1++;
+
+    if(dir==".")return;
+    if(dir==".."){
+      if(current_dir)current_dir=current_dir->dir;
+      return;
+    }
+
+    file_system_by_name::iterator it=fs.find(
+      boost::make_tuple(current_dir,dir));
+    if(it==fs.end()){
+      std::cout<<"non-existent directory"<<std::endl;
+      return;
+    }
+    if(!it->is_dir){
+      std::cout<<dir<<" is not a directory"<<std::endl;
+      return;
+    }
+    current_dir=&*it;
+  }
+};
+static command_cd cd;
+
+/* ls: syntax ls [-s] */
+
+class command_ls:public command
+{
+public:
+  virtual void execute(
+    command_tokenizer::iterator tok1,command_tokenizer::iterator tok2)
+  {
+    std::string option;
+    if(tok1!=tok2)option=*tok1++;
+
+    if(!option.empty()){
+      if(option!="-s"){
+        std::cout<<"incorrect parameter"<<std::endl;
+        return;
+      }
+
+      /* list by size */
+
+      file_system_by_size::iterator it0,it1;
+      boost::tie(it0,it1)=fs_by_size.equal_range(
+        boost::make_tuple(current_dir));
+      std::copy(it0,it1,std::ostream_iterator<file_entry>(std::cout,"\n"));
+
+      return;
+    }
+
+    /* list by name */
+
+    file_system_by_name::iterator it0,it1;
+    boost::tie(it0,it1)=fs.equal_range(boost::make_tuple(current_dir));
+    std::copy(it0,it1,std::ostream_iterator<file_entry>(std::cout,"\n"));
+  }
+};
+static command_ls ls;
+
+/* mkdir: syntax mkdir <directory> */
+
+class command_mkdir:public command
+{
+public:
+  virtual void execute(
+    command_tokenizer::iterator tok1,command_tokenizer::iterator tok2)
+  {
+    std::string dir;
+    if(tok1!=tok2)dir=*tok1++;
+
+    if(dir.empty()){
+      std::cout<<"missing parameter"<<std::endl;
+      return;
+    }
+
+    if(dir=="."||dir==".."){
+      std::cout<<"incorrect parameter"<<std::endl;
+      return;
+    }
+
+    if(!fs.insert(file_entry(dir,0,true,current_dir)).second){
+      std::cout<<"directory already exists"<<std::endl;
+      return;
+    }
+  }
+};
+static command_mkdir mkdir;
+
+/* table of commands, a map from command names to class command pointers */
+
+typedef std::map<std::string,command*> command_table;
+static command_table cmt;
+
+int main()
+{
+  /* fill the file system with some data */
+
+  file_system::iterator it0,it1;
+  
+  fs.insert(file_entry("usr.cfg",240,false,0));
+  fs.insert(file_entry("memo.txt",2430,false,0));
+  it0=fs.insert(file_entry("dev",0,true,0)).first;
+    fs.insert(file_entry("tty0",128,false,&*it0));
+    fs.insert(file_entry("tty1",128,false,&*it0));
+  it0=fs.insert(file_entry("usr",0,true,0)).first;
+    it1=fs.insert(file_entry("bin",0,true,&*it0)).first;
+      fs.insert(file_entry("bjam",172032,false,&*it1));
+  it0=fs.insert(file_entry("home",0,true,0)).first;
+    it1=fs.insert(file_entry("andy",0,true,&*it0)).first;
+      fs.insert(file_entry("logo.jpg",5345,false,&*it1)).first;
+      fs.insert(file_entry("foo.cpp",890,false,&*it1)).first;
+      fs.insert(file_entry("foo.hpp",93,false,&*it1)).first;
+      fs.insert(file_entry("foo.html",750,false,&*it1)).first;
+      fs.insert(file_entry("a.obj",12302,false,&*it1)).first;
+      fs.insert(file_entry(".bash_history",8780,false,&*it1)).first;
+    it1=fs.insert(file_entry("rachel",0,true,&*it0)).first;
+      fs.insert(file_entry("test.py",650,false,&*it1)).first;
+      fs.insert(file_entry("todo.txt",241,false,&*it1)).first;
+      fs.insert(file_entry(".bash_history",9510,false,&*it1)).first;
+
+  /* fill the command table */
+
+  cmt["cd"]   =&cd;
+  cmt["ls"]   =&ls;
+  cmt["mkdir"]=&mkdir;
+
+  /* main looop */
+
+  for(;;){
+    /* print out the current directory and the prompt symbol */
+
+    if(current_dir)std::cout<<current_dir->name;
+    std::cout<<">";
+
+    /* get an input line from the user: if empty, exit the program */
+
+    std::string com;
+    std::getline(std::cin,com);
+    command_tokenizer tok(com,boost::char_separator<char>(" \t\n"));
+    if(tok.begin()==tok.end())break; /* null command, exit */
+
+    /* select the corresponding command and execute it */
+
+    command_table::iterator it=cmt.find(*tok.begin());
+    if(it==cmt.end()){
+      std::cout<<"invalid command"<<std::endl;
+      continue;
+    }
+
+    it->second->execute(boost::next(tok.begin()),tok.end());
+  }
+  
+  return 0;
+}