FEATURE: Type deduction for BOOST_FUSION_ADAPT_STRUCT_C_BASE, with preliminary support for providing or deducing the type.

include/boost/fusion/adapted/struct/adapt_struct.hpp

@@ -6,12 +6,16 @@
     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 ==============================================================================*/
 
+#define BOOST_PP_VARIADICS 1
+
 #ifndef BOOST_FUSION_ADAPTED_STRUCT_ADAPT_STRUCT_HPP
 #define BOOST_FUSION_ADAPTED_STRUCT_ADAPT_STRUCT_HPP
 
 #include <boost/fusion/support/config.hpp>
 #include <boost/preprocessor/cat.hpp>
 #include <boost/preprocessor/empty.hpp>
+#include <boost/preprocessor/variadic/to_seq.hpp>
+#include <boost/preprocessor/variadic/size.hpp>
 #include <boost/type_traits/add_reference.hpp>
 #include <boost/type_traits/is_const.hpp>
 #include <boost/type_traits/add_const.hpp>
@@ -41,6 +45,15 @@
     BOOST_FUSION_ADAPT_STRUCT_C_BASE(                                           \
         TEMPLATE_PARAMS_SEQ,NAME_SEQ,I,BOOST_PP_EMPTY,ATTRIBUTE,2)
 
+#define BOOST_FUSION_ADAPT_STRUCT_C_AUTO(TEMPLATE_PARAMS_SEQ, NAME_SEQ, I, ATTRIBUTE) \
+    BOOST_FUSION_ADAPT_STRUCT_C_BASE(                                                 \
+        TEMPLATE_PARAMS_SEQ,                                                          \
+        NAME_SEQ,                                                                     \
+        I,                                                                            \
+        BOOST_PP_EMPTY,                                                               \
+        ATTRIBUTE,                                                                    \
+        1)
+
 #define BOOST_FUSION_ADAPT_TPL_STRUCT(TEMPLATE_PARAMS_SEQ,NAME_SEQ, ATTRIBUTES) \
     BOOST_FUSION_ADAPT_STRUCT_BASE(                                             \
         (1)TEMPLATE_PARAMS_SEQ,                                                 \
@@ -60,6 +73,34 @@
         BOOST_PP_CAT(BOOST_FUSION_ADAPT_STRUCT_FILLER_0(0,0)ATTRIBUTES,_END),   \
         BOOST_FUSION_ADAPT_STRUCT_C)
 
+
+
+
+
+
+#define BOOST_FUSION_ADAPT_STRUCT_FILLER_NEWAPI__0(...)                                \
+    ((__VA_ARGS__)) BOOST_FUSION_ADAPT_STRUCT_FILLER_NEWAPI__1
+#define BOOST_FUSION_ADAPT_STRUCT_FILLER_NEWAPI__1(...)                                \
+    ((__VA_ARGS__)) BOOST_FUSION_ADAPT_STRUCT_FILLER_NEWAPI__0
+#define BOOST_FUSION_ADAPT_STRUCT_FILLER_NEWAPI__0_END
+#define BOOST_FUSION_ADAPT_STRUCT_FILLER_NEWAPI__1_END
+
+
+#define BOOST_FUSION_ADAPT_STRUCT_NEWAPI(NAME, ATTRIBUTES)                      \
+    BOOST_FUSION_ADAPT_STRUCT_BASE(                                             \
+        (0),                                                                    \
+        (0)(NAME),                                                              \
+        struct_tag,                                                             \
+        0,                                                                      \
+        BOOST_PP_CAT(BOOST_FUSION_ADAPT_STRUCT_FILLER_NEWAPI__0(0,0)ATTRIBUTES,_END),                                  \
+        BOOST_FUSION_ADAPT_STRUCT_C_AUTO)
+
+
+
+
+
+
+
 #define BOOST_FUSION_ADAPT_STRUCT_AS_VIEW(NAME, ATTRIBUTES)                     \
     BOOST_FUSION_ADAPT_STRUCT_BASE(                                             \
         (0),                                                                    \

include/boost/fusion/adapted/struct/detail/adapt_base.hpp

@@ -31,6 +31,9 @@
 #include <boost/mpl/identity.hpp>
 #include <boost/type_traits/add_const.hpp>
 
+#include <boost/typeof/typeof.hpp> 
+
+
 #define BOOST_FUSION_ADAPT_STRUCT_UNPACK_NAME_TEMPLATE_PARAMS(SEQ)              \
     BOOST_PP_SEQ_HEAD(SEQ)<BOOST_PP_SEQ_ENUM(BOOST_PP_SEQ_TAIL(SEQ))>           \
     BOOST_PP_EMPTY()
@@ -55,6 +58,13 @@
         BOOST_FUSION_ADAPT_STRUCT_UNPACK_TEMPLATE_PARAMS_IMPL,                  \
         BOOST_PP_TUPLE_EAT(1))(SEQ)
 
+#define BOOST_FUSION_ATTRIBUTE_TYPE_DEDUCE(NAME_SEQ, ATTRIBUTE, ATTRIBUTE_TUPEL_SIZE)\
+    BOOST_TYPEOF(BOOST_FUSION_ADAPT_STRUCT_UNPACK_NAME(NAME_SEQ)::BOOST_PP_TUPLE_ELEM(ATTRIBUTE_TUPEL_SIZE, 0, ATTRIBUTE) \
+        )
+
+#define BOOST_FUSION_GET_GIVEN_TYPE(NAME_SEQ, ATTRIBUTE, ATTRIBUTE_TUPEL_SIZE)      \
+    BOOST_PP_TUPLE_ELEM(ATTRIBUTE_TUPEL_SIZE, 0, ATTRIBUTE)
+
 #ifdef BOOST_NO_PARTIAL_SPECIALIZATION_IMPLICIT_DEFAULT_ARGS
 #   define BOOST_FUSION_ADAPT_STRUCT_TAG_OF_SPECIALIZATION(                     \
         MODIFIER, TEMPLATE_PARAMS_SEQ, NAME_SEQ, TAG)                           \
@@ -118,7 +128,9 @@
     >                                                                           \
     {                                                                           \
         typedef                                                                 \
-            BOOST_PP_TUPLE_ELEM(ATTRIBUTE_TUPEL_SIZE, 0, ATTRIBUTE)             \ //TODO: DAM Typeof can be added here
+            BOOST_PP_IF(BOOST_PP_LESS(/*ATTRIBUTE_TUPEL_SIZE*/1,2),             \
+                BOOST_FUSION_ATTRIBUTE_TYPE_DEDUCE, BOOST_FUSION_GET_GIVEN_TYPE \
+                )(NAME_SEQ, ATTRIBUTE, ATTRIBUTE_TUPEL_SIZE)                    \
         attribute_type;                                                         \
         BOOST_FUSION_ADAPT_STRUCT_MSVC_REDEFINE_TEMPLATE_PARAMS(                \
             TEMPLATE_PARAMS_SEQ)                                                \
@@ -143,7 +155,9 @@
             call(Seq& seq)                                                      \
             {                                                                   \
                 return seq.PREFIX()                                             \
-                    BOOST_PP_TUPLE_ELEM(ATTRIBUTE_TUPEL_SIZE, 1, ATTRIBUTE);    \
+                    BOOST_PP_TUPLE_ELEM(ATTRIBUTE_TUPEL_SIZE,                   \
+                        BOOST_PP_IF(BOOST_PP_LESS(ATTRIBUTE_TUPEL_SIZE,2), 0, 1),\
+                          ATTRIBUTE);                                           \
             }                                                                   \
         };                                                                      \
     };                                                                          \

test/sequence/adapt_struct.cpp

@@ -56,22 +56,22 @@ namespace ns
 #endif
 }
 
-BOOST_FUSION_ADAPT_STRUCT(
+BOOST_FUSION_ADAPT_STRUCT_NEWAPI(
     ns::point,
-    (int, x)
+    (x)
-    (int, y)
+    (y)
 )
 
 #if !BOOST_WORKAROUND(__GNUC__,<4)
-BOOST_FUSION_ADAPT_STRUCT(
+BOOST_FUSION_ADAPT_STRUCT_NEWAPI(
     ns::point_with_private_attributes,
-    (int, x)
+    (x)
-    (int, y)
+    (y)
 )
 #endif
 
 struct s { int m; };
-BOOST_FUSION_ADAPT_STRUCT(s, (int, m))
+BOOST_FUSION_ADAPT_STRUCT_NEWAPI(s, (m))
 
 int
 main()