From b4c150497532296cf8d7e4d9a1011d2f5046f8eb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philipp=20M=C3=B6ller?=
 <Philipp.Moeller@geometryfactory.com>
Date: Wed, 22 Jun 2011 15:27:48 +0000
Subject: [PATCH] Added conversion from optional<variant<...>>

---
 STL_Extension/include/CGAL/Object.h              | 12 +++++++++---
 STL_Extension/test/STL_Extension/test_Object.cpp | 10 +++++++++-
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/STL_Extension/include/CGAL/Object.h b/STL_Extension/include/CGAL/Object.h
index c2fe6452540..7cddf7ec320 100644
--- a/STL_Extension/include/CGAL/Object.h
+++ b/STL_Extension/include/CGAL/Object.h
@@ -34,6 +34,7 @@
 #include <typeinfo>
 
 #include <boost/variant.hpp>
+#include <boost/optional.hpp>
 
 namespace CGAL {
 
@@ -111,9 +112,14 @@ class Object
     Object(const T& t) {
       // we cannot invoke another ctor from here, so we have to behave
       // like the copy ctor of our base
-      CGAL::Object tmp = boost::apply_visitor(Object_from_variant(), t);
-      this->ptr = tmp.ptr;
-      (this->ptr)->add_reference();
+      if(t) {
+        CGAL::Object tmp = boost::apply_visitor(Object_from_variant(), *t);
+        this->ptr = tmp.ptr;
+        (this->ptr)->add_reference();
+      } else {
+	typedef Wrapper<Empty>  Wrap;
+        ptr = new Wrap(Empty());
+      }
     }
 
     template <class T>
diff --git a/STL_Extension/test/STL_Extension/test_Object.cpp b/STL_Extension/test/STL_Extension/test_Object.cpp
index cfcc861db64..e55d796185b 100644
--- a/STL_Extension/test/STL_Extension/test_Object.cpp
+++ b/STL_Extension/test/STL_Extension/test_Object.cpp
@@ -3,11 +3,15 @@
 #include <CGAL/Object.h>
 #include <CGAL/assertions.h>
 
+#include <boost/variant.hpp>
+#include <boost/optional.hpp>
+
 void test_object() {
   int i = 0;
   double j = 0.0;
-  boost::variant<int, char, double> v = 23;
+  boost::optional< boost::variant<int, char, double> > v(23);
   CGAL::Object o = v;
+  CGAL_assertion(!o.empty());
   CGAL_assertion(CGAL::assign(i, o));
   CGAL_assertion(i == 23);
   //reassign the variant and assign it again
@@ -16,6 +20,10 @@ void test_object() {
   CGAL_assertion(!CGAL::assign(i, o));
   CGAL_assertion(CGAL::assign(j, o));
   CGAL_assertion(j == 2.0);
+  //empty optional
+  boost::optional< boost::variant<int, char, double> > v2;
+  CGAL::Object o2 = v2;
+  CGAL_assertion(o2.empty());
 }
 
 int main() {