From 8e4e6a2fc2e4d5608123d37c3659f4f9f711ded0 Mon Sep 17 00:00:00 2001
From: Bruno Lalande <bruno.lalande@gmail.com>
Date: Sun, 4 Dec 2011 02:00:25 +0000
Subject: [PATCH] New mechanism for easy checking of implementation status.

[SVN r75796]
---
 .../tools/support_status/support_status.cpp   | 89 +++++++++++++++++++
 .../boost/geometry/algorithms/distance.hpp    |  7 +-
 .../geometry/algorithms/not_implemented.hpp   | 34 +++++++
 3 files changed, 128 insertions(+), 2 deletions(-)
 create mode 100644 doc/src/docutils/tools/support_status/support_status.cpp
 create mode 100644 include/boost/geometry/algorithms/not_implemented.hpp

diff --git a/doc/src/docutils/tools/support_status/support_status.cpp b/doc/src/docutils/tools/support_status/support_status.cpp
new file mode 100644
index 000000000..248a7bc13
--- /dev/null
+++ b/doc/src/docutils/tools/support_status/support_status.cpp
@@ -0,0 +1,89 @@
+#include <iostream>
+
+#include <boost/type_traits/is_base_of.hpp>
+#include <boost/mpl/for_each.hpp>
+#include <boost/mpl/vector.hpp>
+
+#define BOOST_GEOMETRY_IMPLEMENTATION_STATUS_BUILD true
+#include <boost/geometry/core/cs.hpp>
+#include <boost/geometry/geometries/geometries.hpp>
+#include <boost/geometry/algorithms/distance.hpp>
+#include <boost/geometry/strategies/cartesian/distance_pythagoras.hpp>
+
+
+template <typename Tag1, typename Tag2, typename G1, typename G2>
+struct check
+  : boost::geometry::dispatch::distance<
+        Tag1,
+        Tag2,
+        G1,
+        G2,
+        boost::geometry::strategy_tag_distance_point_point,
+        typename boost::geometry::strategy::distance::services::default_strategy<
+            boost::geometry::point_tag,
+            G1,
+            G2
+        >::type
+    >
+{};
+
+
+typedef boost::geometry::cs::cartesian cartesian;
+
+typedef boost::geometry::model::point<double, 2, cartesian> point_type;
+typedef boost::geometry::model::linestring<point_type>      line_type;
+typedef boost::geometry::model::polygon<point_type>         polygon_type;
+typedef boost::geometry::model::box<point_type>             box_type;
+typedef boost::geometry::model::ring<point_type>            ring_type;
+typedef boost::geometry::model::segment<point_type>         segment_type;
+
+typedef boost::mpl::vector<
+    point_type,
+    line_type,
+    polygon_type,
+    box_type,
+    ring_type,
+    segment_type
+> types;
+
+
+
+template <class T1>
+struct tester
+{
+    template <typename T2>
+    void operator()(T2)
+    {
+        typedef typename boost::geometry::tag<T1>::type tag1;
+        typedef typename boost::geometry::tag<T2>::type tag2;
+
+        if (boost::is_base_of<boost::geometry::not_implemented, check<tag1, tag2, T1, T2> >::type::value
+         && boost::is_base_of<boost::geometry::not_implemented, check<tag2, tag1, T2, T1> >::type::value)
+        {
+            std::cout << "-\t";
+        }
+        else
+        {
+            std::cout << "OK\t";
+        }
+    }
+};
+
+template <>
+struct tester<void>
+{
+    template <typename T>
+    void operator()(T)
+    {
+        boost::mpl::for_each<types>(tester<T>());
+        std::cout << std::endl;
+    }
+};
+
+
+int main()
+{
+    boost::mpl::for_each<types>(tester<void>());
+
+    return 0;
+}
diff --git a/include/boost/geometry/algorithms/distance.hpp b/include/boost/geometry/algorithms/distance.hpp
index c28d4a6c0..9f92dbbc7 100644
--- a/include/boost/geometry/algorithms/distance.hpp
+++ b/include/boost/geometry/algorithms/distance.hpp
@@ -28,6 +28,8 @@
 #include <boost/geometry/core/reverse_dispatch.hpp>
 #include <boost/geometry/core/tag_cast.hpp>
 
+#include <boost/geometry/algorithms/not_implemented.hpp>
+
 #include <boost/geometry/geometries/segment.hpp>
 #include <boost/geometry/geometries/concepts/check.hpp>
 
@@ -253,11 +255,12 @@ template
     typename Geometry1, typename Geometry2,
     typename StrategyTag, typename Strategy
 >
-struct distance
+struct distance: boost::geometry::not_implemented
 {
     BOOST_MPL_ASSERT_MSG
         (
-            false, NOT_OR_NOT_YET_IMPLEMENTED_FOR_THIS_GEOMETRY_TYPE
+            BOOST_GEOMETRY_IMPLEMENTATION_STATUS_BUILD,
+            NOT_OR_NOT_YET_IMPLEMENTED_FOR_THIS_GEOMETRY_TYPE
             , (types<Geometry1, Geometry2>)
         );
 };
diff --git a/include/boost/geometry/algorithms/not_implemented.hpp b/include/boost/geometry/algorithms/not_implemented.hpp
new file mode 100644
index 000000000..76addd9d7
--- /dev/null
+++ b/include/boost/geometry/algorithms/not_implemented.hpp
@@ -0,0 +1,34 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+
+// Copyright (c) 2008-2011 Bruno Lalande, Paris, France.
+// Copyright (c) 2007-2011 Barend Gehrels, Amsterdam, the Netherlands.
+// Copyright (c) 2009-2011 Mateusz Loskot, London, UK.
+
+// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
+// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+
+#ifndef BOOST_GEOMETRY_ALGORITHMS_NOT_IMPLEMENTED_HPP
+#define BOOST_GEOMETRY_ALGORITHMS_NOT_IMPLEMENTED_HPP
+
+
+namespace boost { namespace geometry
+{
+
+
+#ifndef BOOST_GEOMETRY_IMPLEMENTATION_STATUS_BUILD
+# define BOOST_GEOMETRY_IMPLEMENTATION_STATUS_BUILD false
+#endif
+
+
+struct not_implemented {};
+
+
+}} // namespace boost::geometry
+
+
+#endif // BOOST_GEOMETRY_ALGORITHMS_NOT_IMPLEMENTED_HPP