Help on DDJ article on template meta-programming

Dear all,

I'm experiencing with meta-programming (I'm a newbie).
I've found an interesting article by Thomas Becker at
http://www.ddj.com/cpp/184401565

Unfortunately the code does not compile: with GCC 4.1.1 I get 18
errors.
The command used for compiling is:
  g++ -Wall -Wextra -ansi meta.cpp
where meta.cpp is the source code.

I've tried to make some adjustments and I end up with "only" 2 errors.

Now I don't understand why my final version does not compile.

Can someone able to explain why this not work and how to fix it?

Here below is the code:

---[begin code]---
#include <iostream>

/// META-IF

template <bool Cond, typename ThenType, typename ElseType>
struct meta_if
{
    typedef ThenType type;
};

template <typename ThenType, typename ElseType>
struct meta_if<false, ThenType, ElseType>
{
    typedef ElseType type;
};

/// META-IS-REFERENCE

template <typename T>
struct meta_is_reference
{
    enum { value = false };
    //static const bool value = false;
};

template <typename T>
struct meta_is_reference<T&>
{
    enum { value = true };
    //static const bool value = true;
};

/// META-REMOVE-REFERENCE

template <typename T>
struct meta_remove_reference
{
    typedef T type;
};

template <typename T>
struct meta_remove_reference<T&>
{
    typedef T type;
};

/// META-IDENTITY

template <typename T>
struct meta_identity
{
    typedef T type;
};

/// META-NON-REFERENCE

template <typename T>
struct meta_non_reference
{
    typedef typename meta_if<
                typename meta_is_reference<T>::value,
                typename meta_remove_reference<T>::type,
                typename meta_identity<T>::type
            >::type type;
};

int main()
{
    typedef meta_non_reference<int>::type my_type1;
    my_type1 x1;

    typedef meta_non_reference<int&>::type my_type2;
    my_type2 x2;
}
---[end code]---

Thank you very much!!

Best,

-- Marco

--
      [ See http://www.gotw.ca/resources/clcm.htm for info about ]
      [ comp.lang.c++.moderated. First time posters: Do this! ]