Work around bug in g++4.6

I'm going to have to start dropping support for older compilers soon.

The 4.6 line is 4 years old now, and 4.7 has these issues fixed

include/chaiscript/chaiscript_defines.hpp

@@ -35,6 +35,10 @@
 #define CHAISCRIPT_HAS_THREAD_LOCAL
 #endif
 
+#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+#define CHAISCRIPT_GCC_4_6
+#endif
+
 #if (defined(__GNUC__) && __GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7) || defined(CHAISCRIPT_MSVC) || defined(__llvm__)
 #define CHAISCRIPT_OVERRIDE override
 #else

include/chaiscript/dispatchkit/proxy_functions_detail.hpp

@@ -53,6 +53,113 @@ namespace chaiscript
   {
     namespace detail
     {
+      /**
+       * Used by Proxy_Function_Impl to return a list of all param types
+       * it contains.
+       */
+      template<typename Ret, typename ... Params>
+        std::vector<Type_Info> build_param_type_list(Ret (*)(Params...))
+        {
+          /// \note somehow this is responsible for a large part of the code generation
+          return { user_type<Ret>(), user_type<Params>()... };
+        }
+
+
+#ifdef CHAISCRIPT_GCC_4_6 
+      /// \todo REMOVE THIS WHEN WE DROP G++4.6
+      
+      // Forward declaration
+      template<typename ... Rest> 
+        struct Try_Cast; 
+
+      template<typename Param, typename ... Rest>
+        struct Try_Cast<Param, Rest...>
+        {
+          static void do_try(const std::vector<Boxed_Value> &params, size_t generation, const Type_Conversions &t_conversions)
+          {
+            boxed_cast<Param>(params[generation], &t_conversions);
+            Try_Cast<Rest...>::do_try(params, generation+1, t_conversions);
+          }
+        };
+
+      // 0th case
+      template<>
+        struct Try_Cast<>
+        {
+          static void do_try(const std::vector<Boxed_Value> &, size_t, const Type_Conversions &)
+          {
+          }
+        };
+
+
+      /**
+       * Used by Proxy_Function_Impl to determine if it is equivalent to another
+       * Proxy_Function_Impl object. This function is primarily used to prevent
+       * registration of two functions with the exact same signatures
+       */
+      template<typename Ret, typename ... Params>
+        bool compare_types_cast(Ret (*)(Params...),
+             const std::vector<Boxed_Value> &params, const Type_Conversions &t_conversions)
+       {
+          try {
+            Try_Cast<Params...>::do_try(params, 0, t_conversions);
+          } catch (const exception::bad_boxed_cast &) {
+            return false;
+          }
+
+          return true;
+        }
+
+      template<typename Ret, int count, typename ... Params>
+        struct Call_Func
+        {
+
+          template<typename ... InnerParams>
+          static Ret do_call(const std::function<Ret (Params...)> &f,
+              const std::vector<Boxed_Value> &params, const Type_Conversions &t_conversions, InnerParams &&... innerparams)
+          {
+            return Call_Func<Ret, count - 1, Params...>::do_call(f, params, t_conversions, std::forward<InnerParams>(innerparams)..., params[sizeof...(Params) - count]);
+          } 
+        };
+
+      template<typename Ret, typename ... Params>
+        struct Call_Func<Ret, 0, Params...>
+        {
+#ifdef CHAISCRIPT_MSVC
+#pragma warning(push)
+#pragma warning(disable : 4100) /// Disable unreferenced formal parameter warning, which only shows up in MSVC I don't think there's any way around it \todo evaluate this
+#endif
+          template<typename ... InnerParams>
+            static Ret do_call(const std::function<Ret (Params...)> &f,
+                const std::vector<Boxed_Value> &, const Type_Conversions &t_conversions, InnerParams &&... innerparams)
+            {
+              return f(boxed_cast<Params>(std::forward<InnerParams>(innerparams), &t_conversions)...);
+            }
+#ifdef CHAISCRIPT_MSVC
+#pragma warning(pop)
+#endif
+        };
+
+      /**
+       * Used by Proxy_Function_Impl to perform typesafe execution of a function.
+       * The function attempts to unbox each parameter to the expected type.
+       * if any unboxing fails the execution of the function fails and
+       * the bad_boxed_cast is passed up to the caller.
+       */
+      template<typename Ret, typename ... Params>
+        Ret call_func(const std::function<Ret (Params...)> &f,
+            const std::vector<Boxed_Value> &params, const Type_Conversions &t_conversions)
+        {
+          if (params.size() == sizeof...(Params))
+          {
+            return Call_Func<Ret, sizeof...(Params), Params...>::do_call(f, params, t_conversions);
+          }
+
+          throw exception::arity_error(static_cast<int>(params.size()), sizeof...(Params));
+        }
+
+#else
+
       template<size_t ... I>
       struct Indexes
       {
@@ -70,16 +177,6 @@ namespace chaiscript
         typedef Indexes<I...> indexes;
       };
 
-      /**
-       * Used by Proxy_Function_Impl to return a list of all param types
-       * it contains.
-       */
-      template<typename Ret, typename ... Params>
-        std::vector<Type_Info> build_param_type_list(Ret (*)(Params...))
-        {
-          /// \note somehow this is responsible for a large part of the code generation
-          return { user_type<Ret>(), user_type<Params>()... };
-        }
 
 
       /**
@@ -135,6 +232,8 @@ namespace chaiscript
           throw exception::arity_error(static_cast<int>(params.size()), sizeof...(Params));
         }
 
+#endif
+
     }
   }