gistfile1.cpp

template <typename T, T def>
struct primitive_t : is_lexical_value<T> {
  typedef T value_type;

  primitive_t() : t(def) {}
  primitive_t(T t) : t(t) {}

  primitive_t& operator=(T a_t) {
    t = a_t;
    return *this;
  }
  operator T() const { return t; }

 private:
  T t;
};

// example
typedef primitive_t<int, 0> angle_t;

struct Camera {
  angle_t angle; // will be 0 by default :D
};