From 455d80c8a6a67f02adf83d3e69e4fab111031e18 Mon Sep 17 00:00:00 2001
From: Marc Glisse <marc.glisse@inria.fr>
Date: Sun, 10 Feb 2019 15:29:25 +0100
Subject: [PATCH] Handle computations the same as constructions.

---
 NewKernel_d/include/CGAL/NewKernel_d/Lazy_cartesian.h | 10 +++++-----
 NewKernel_d/include/CGAL/NewKernel_d/functor_tags.h   |  7 ++++---
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/NewKernel_d/include/CGAL/NewKernel_d/Lazy_cartesian.h b/NewKernel_d/include/CGAL/NewKernel_d/Lazy_cartesian.h
index 0fa5fa99d43..8385d6c42f4 100644
--- a/NewKernel_d/include/CGAL/NewKernel_d/Lazy_cartesian.h
+++ b/NewKernel_d/include/CGAL/NewKernel_d/Lazy_cartesian.h
@@ -63,7 +63,6 @@ namespace internal {
 }
 
 // Whenever a construction takes iterator pairs as input, whether they point to double of Lazy objects, copy the ranges inside the lazy result so they are available for update_exact(). We analyze the input to try and guess where iterator pairs are. I would prefer if each functor had a specific signature (no overload in this layer) so we wouldn't have to guess.
-// FIXME: Lazy_construct_nt is also a construction and needs the same treatment.
 namespace Lazy_internal {
 template<class...>struct typelist{};
 template<int>struct arg_i{};
@@ -155,13 +154,14 @@ class Lazy_rep_XXX :
   }
   // TODO: print_dag needs a specific implementation for Lazy_rep_XXX
 };
+template<class Tag, class LK, class ET>struct Select_converter { typedef typename LK::E2A type; };
+template<class LK, class ET>struct Select_converter<Compute_tag,LK,ET> { typedef To_interval<ET> type; };
 template<typename T, typename LK>
 struct Lazy_construction2 {
   static const bool Protection = true;
 
   typedef typename LK::Approximate_kernel AK;
   typedef typename LK::Exact_kernel EK;
-  typedef typename LK::E2A E2A;
   typedef typename Get_functor<AK, T>::type AC;
   typedef typename Get_functor<EK, T>::type EC;
   typedef typename map_result_tag<T>::type result_tag;
@@ -169,6 +169,7 @@ struct Lazy_construction2 {
   typedef typename Get_type<EK, result_tag>::type ET;
   typedef typename Get_type<LK, result_tag>::type result_type;
   // same as Handle = Lazy< AT, ET, E2A>
+  typedef typename Select_converter<typename Get_functor_category<LK,T>::type, LK, ET>::type E2A;
 
   Lazy_construction2(){}
   Lazy_construction2(LK const&k):ac(k.approximate_kernel()),ec(k.exact_kernel()){}
@@ -225,6 +226,7 @@ struct Lazy_cartesian_types
       typedef typename Select_nth_element_functor<AK_,T>::type AF;
       typedef typename Select_nth_element_functor<EK_,T>::type EF;
 
+      // TODO: we should use Lazy_construction2, but this seems ok for now, we never construct iterators from iterators.
       typedef typename internal::Lazy_construction_maybe_nt<
 	Kernel_, AF, EF, is_NT_tag<Vt>::value
 	>::type nth_elem;
@@ -298,9 +300,7 @@ struct Lazy_cartesian :
 	    typedef Filtered_predicate2<FE,FA,C2E,C2A> type;
     };
     template<class T,class D> struct Functor<T,D,Compute_tag> {
-	    typedef typename Get_functor<Approximate_kernel, T>::type FA;
-	    typedef typename Get_functor<Exact_kernel, T>::type FE;
-	    typedef Lazy_construction_nt<Kernel,FA,FE> type;
+	    typedef Lazy_construction2<T,Kernel> type;
     };
     template<class T,class D> struct Functor<T,D,Construct_tag> {
 	    typedef Lazy_construction2<T,Kernel> type;
diff --git a/NewKernel_d/include/CGAL/NewKernel_d/functor_tags.h b/NewKernel_d/include/CGAL/NewKernel_d/functor_tags.h
index 58fbef78dd7..ebe4eae4382 100644
--- a/NewKernel_d/include/CGAL/NewKernel_d/functor_tags.h
+++ b/NewKernel_d/include/CGAL/NewKernel_d/functor_tags.h
@@ -199,7 +199,11 @@ namespace CGAL {
 	  typedef Null_tag value_tag;
 	};
 
+	template<class>struct map_result_tag{typedef Null_type type;};
+	template<class T>struct map_result_tag<Construct_ttag<T> >{typedef T type;};
+
 #define CGAL_DECL_COMPUTE(X) struct X##_tag {}; \
+	template<>struct map_result_tag<X##_tag>{typedef FT_tag type;}; \
 	template<class A,class B,class C>struct Get_functor_category<A,X##_tag,B,C>{typedef Compute_tag type;}
 	CGAL_DECL_COMPUTE(Compute_point_cartesian_coordinate);
 	CGAL_DECL_COMPUTE(Compute_vector_cartesian_coordinate);
@@ -237,9 +241,6 @@ namespace CGAL {
 	CGAL_DECL_ITER_OBJ(Point_cartesian_const_iterator, FT, Compute_point_cartesian_coordinate, Point);
 #undef CGAL_DECL_ITER_OBJ
 
-	template<class>struct map_result_tag{typedef Null_type type;};
-	template<class T>struct map_result_tag<Construct_ttag<T> >{typedef T type;};
-
 	template<class A,class T,class B,class C>struct Get_functor_category<A,Construct_ttag<T>,B,C> :
 	  boost::mpl::if_c<iterator_tag_traits<T>::is_iterator,
 			   Construct_iterator_tag,