Phil Nash

    enum ComparisonResult
    {
        less = -1,
        equal = 0,
        greater = 1
    };

    template<typename T>
    class CompareChain : std::binary_function<const T&, const T&, bool>
    {
        typedef boost::function<ComparisonResult( const T& lhs, const T& rhs )> CompareFunctor;
    public:
        CompareChain( const CompareFunctor& f1 )
        {
            functions.push_back( f1 );
        }

        CompareChain( const CompareFunctor& f1, const CompareFunctor& f2 )
        {
            functions.push_back( f1 );
            functions.push_back( f2 );
        }

        CompareChain( const CompareFunctor& f1, const CompareFunctor& f2, const CompareFunctor& f3 )
        {
            functions.push_back( f1 );
            functions.push_back( f2 );
            functions.push_back( f3 );
        }

        bool operator()( const T& lhs, const T& rhs ) const
        {
            BOOST_FOREACH( CompareFunctor f, functions )
            {
                switch( f( lhs, rhs ) )
                {
                    case less:
                        return true;
                    case greater:
                        return false;
                }
            }
            return false;
        }
    private:
        std::vector<CompareFunctor> functions;
    };