message: Code review : Factorize some templates
diff: @@ -114,17 +114,8 @@ struct Value_from_iterator<complexity::SAFE, false> {
  }
  };
  -template <>
  -struct Value_from_iterator<complexity::EXACT, true> {
  - template <typename Iterator>
  - static double perform(Iterator it) {
  - // In EXACT mode, we are with Epeck or Epick with EXACT value set to CGAL::Tag_true.
  - return CGAL::to_double(it->exact());
  - }
  -};
  -
  -template <>
  -struct Value_from_iterator<complexity::EXACT, false> {
  +template<bool Weighted_or_periodic>
  +struct Value_from_iterator<complexity::EXACT,Weighted_or_periodic>{
  template <typename Iterator>
  static double perform(Iterator it) {
  // In EXACT mode, we are with Epeck or Epick with EXACT value set to CGAL::Tag_true.
  @@ -190,14 +181,11 @@ class Alpha_complex_3d {
  template <typename Predicates, bool Weighted_version, bool Periodic_version>
  struct Kernel_3 {};
  - template <typename Predicates>
  - struct Kernel_3<Predicates, false, false> {
  - using Kernel = Predicates;
  - };
  - template <typename Predicates>
  - struct Kernel_3<Predicates, true, false> {
  + template <typename Predicates, bool Is_periodic>
  + struct Kernel_3<Predicates, Is_periodic, false> {
  using Kernel = Predicates;
  };
  +
  template <typename Predicates>
  struct Kernel_3<Predicates, false, true> {
  using Kernel = CGAL::Periodic_3_Delaunay_triangulation_traits_3<Predicates>;
  