From 3612acb0ef66afc84fa8ab220fd138475dbe3937 Mon Sep 17 00:00:00 2001
From: Dan Marsden <danmarsden@yahoo.co.uk>
Date: Fri, 6 Jul 2007 20:47:11 +0000
Subject: [PATCH] adding working converting ctors for zero length sequences

[SVN r38155]
---
 .../fusion/sequence/container/deque/deque.hpp  | 10 +++++++++-
 .../container/deque/detail/keyed_element.hpp   | 18 ++++++++++++++++++
 .../sequence/container/vector/vector10.hpp     |  6 ++++++
 include/boost/fusion/support/void.hpp          |  8 ++++++++
 4 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 include/boost/fusion/support/void.hpp

diff --git a/include/boost/fusion/sequence/container/deque/deque.hpp b/include/boost/fusion/sequence/container/deque/deque.hpp
index ababdd4c..884899f8 100644
--- a/include/boost/fusion/sequence/container/deque/deque.hpp
+++ b/include/boost/fusion/sequence/container/deque/deque.hpp
@@ -20,20 +20,23 @@
 #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
 #include <boost/type_traits/add_reference.hpp>
 #include <boost/type_traits/add_const.hpp>
+#include <boost/type_traits/is_convertible.hpp>
 
 #include <boost/fusion/sequence/container/deque/deque_fwd.hpp>
 #include <boost/fusion/sequence/container/deque/detail/value_at_impl.hpp>
 #include <boost/fusion/sequence/container/deque/detail/at_impl.hpp>
 #include <boost/fusion/sequence/container/deque/detail/begin_impl.hpp>
 #include <boost/fusion/sequence/container/deque/detail/end_impl.hpp>
+#include <boost/fusion/sequence/intrinsic/begin.hpp>
 #include <boost/mpl/bool.hpp>
 
 #include <boost/fusion/support/sequence_base.hpp>
+#include <boost/fusion/support/void.hpp>
+#include <boost/utility/enable_if.hpp>
 
 namespace boost { namespace fusion {
 
     struct deque_tag;
-    struct void_;
 
     template<BOOST_PP_ENUM_PARAMS(FUSION_MAX_DEQUE_SIZE, typename T)>
     struct deque
@@ -63,6 +66,11 @@ namespace boost { namespace fusion {
             : base(seq)
             {}
 
+        template<typename Sequence>
+            deque(Sequence const& seq, typename disable_if<is_convertible<Sequence, T0> >::type* dummy = 0)
+            : base(base::from_iterator(fusion::begin(seq)))
+            {}
+
         template <BOOST_PP_ENUM_PARAMS(FUSION_MAX_DEQUE_SIZE, typename U)>
         deque&
         operator=(deque<BOOST_PP_ENUM_PARAMS(FUSION_MAX_DEQUE_SIZE, U)> const& rhs)
diff --git a/include/boost/fusion/sequence/container/deque/detail/keyed_element.hpp b/include/boost/fusion/sequence/container/deque/detail/keyed_element.hpp
index 4f032d6f..177f68ac 100644
--- a/include/boost/fusion/sequence/container/deque/detail/keyed_element.hpp
+++ b/include/boost/fusion/sequence/container/deque/detail/keyed_element.hpp
@@ -11,6 +11,9 @@
 #include <boost/type_traits/add_reference.hpp>
 #include <boost/type_traits/add_const.hpp>
 
+#include <boost/fusion/iterator/deref.hpp>
+#include <boost/fusion/iterator/next.hpp>
+
 namespace boost { namespace fusion {
 
     struct fusion_sequence_tag;
@@ -21,6 +24,13 @@ namespace detail {
     {
         typedef fusion_sequence_tag tag;
         void get();
+
+        template<typename It>
+        static nil_keyed_element 
+        from_iterator(It const&)
+        {
+            return nil_keyed_element();
+        }
     };
 
     template<typename Key, typename Value, typename Rest>
@@ -31,6 +41,14 @@ namespace detail {
         typedef fusion_sequence_tag tag;
         using Rest::get;
 
+        template<typename It>
+        static keyed_element
+        from_iterator(It const& it)
+        {
+            return keyed_element(
+                *it, base::from_iterator(fusion::next(it)));
+        }
+
         template<typename U, typename Rst>
         keyed_element(keyed_element<Key, U, Rst> const& rhs)
             : Rest(rhs.get_base()), value_(rhs.value_)
diff --git a/include/boost/fusion/sequence/container/vector/vector10.hpp b/include/boost/fusion/sequence/container/vector/vector10.hpp
index fa96ee56..6ff80a0c 100644
--- a/include/boost/fusion/sequence/container/vector/vector10.hpp
+++ b/include/boost/fusion/sequence/container/vector/vector10.hpp
@@ -47,6 +47,12 @@ namespace boost { namespace fusion
         typedef mpl::false_ is_view;
         typedef random_access_traversal_tag category;
         typedef mpl::int_<0> size;
+
+        vector0() {}
+
+        template<typename Sequence>
+        vector0(Sequence const& seq)
+        {}
     };
 
 // expand vector1 to vector10
diff --git a/include/boost/fusion/support/void.hpp b/include/boost/fusion/support/void.hpp
new file mode 100644
index 00000000..63275b11
--- /dev/null
+++ b/include/boost/fusion/support/void.hpp
@@ -0,0 +1,8 @@
+#if !defined(BOOST_FUSION_SUPPORT_VOID_20070706_2125)
+#define BOOST_FUSION_SUPPORT_VOID_20070706_2125
+
+namespace boost { namespace fusion {
+    struct void_ {};
+}}
+
+#endif