A hefty slice of changes for functions on the proxy. Not necessary, but was fun to get around MSVC's ICE errors.

sol/function.hpp

@@ -65,9 +65,14 @@ public:
     void operator()(Args&&... args) {
 	    call<>(std::forward<Args>(args)...);
     }
+
+    template<typename... Ret, typename... Args>
+    typename multi_return<Ret...>::type operator()(types<Ret...>, Args&&... args) {
+	    return call<Ret...>(std::forward<Args>(args)...);
+    }
     
     template<typename... Ret, typename... Args>
-    auto call(Args&&... args) -> decltype(invoke(types<Ret...>(), sizeof...(Args))) {
+    typename multi_return<Ret...>::type call(Args&&... args) {
         push();
         stack::push_args(state(), std::forward<Args>(args)...);
         return invoke(types<Ret...>(), sizeof...(Args));

sol/stack.hpp

@@ -45,7 +45,7 @@ inline T get_unsigned(lua_State* L, std::false_type, int index = -1) {
 template<typename T>
 inline T get_arithmetic(lua_State* L, std::false_type, int index = -1) {
     // T is a floating point
-    return lua_tonumber(L, index);
+    return static_cast<T>(lua_tonumber(L, index));
 }
 
 template<typename T>

sol/table.hpp

@@ -118,6 +118,21 @@ private:
         operator U() const {
             return t.get<U>(key);
         }
+
+        template<typename... Args>
+        void operator()( Args&&... args ) {
+            call<>( std::forward<Args>( args )... );
+	   }
+
+        template<typename... Ret, typename... Args>
+        typename multi_return<Ret...>::type operator()(types<Ret...>, Args&&... args) {
+            return call<Ret...>(std::forward<Args>(args)...);
+        }
+
+        template<typename... Ret, typename... Args>
+        typename multi_return<Ret...>::type call(Args&&... args) {
+            return t.get<function>(key)(types<Ret...>(), std::forward<Args>(args)...);
+        }
     };
 
     template<typename T, typename TFx>

sol/traits.hpp

@@ -22,6 +22,7 @@
 #ifndef SOL_TRAITS_HPP
 #define SOL_TRAITS_HPP
 
+#include "tuple.hpp"
 #include <type_traits>
 
 namespace sol {
@@ -62,6 +63,21 @@ struct is_function_impl<T, true> {
 };
 } // detail
 
+template <typename... Args>
+struct multi_return {
+    typedef std::tuple<Args...> type;
+};
+
+template <typename T>
+struct multi_return<T> {
+    typedef T type;
+};
+
+template <>
+struct multi_return<> : types<>{
+    typedef void type;
+};
+
 template<bool B>
 using Bool = std::integral_constant<bool, B>;
 

sol/types.hpp

@@ -113,6 +113,8 @@ template<>
 inline type type_of<bool>() {
     return type::boolean;
 }
+
+inline bool operator==(nil_t, nil_t) { return true; }
 } // sol
 
 #endif // SOL_TYPES_HPP

tests.cpp

@@ -112,18 +112,40 @@ TEST_CASE("simple/callLambda", "A C++ lambda is exposed to lua and called") {
 }
 
 TEST_CASE("advanced/callLambdaReturns", "Checks for lambdas returning values") {
+    const static std::string lol = "lol", str = "str";
+    const static std::tuple<int, float, double, std::string> heh_tuple = std::make_tuple(1, 6.28f, 3.14, std::string("heh"));
     sol::state lua;
 
     REQUIRE_NOTHROW(lua.set_function("a", [ ] { return 42; }));
+    REQUIRE(lua["a"]( sol::types<int>() ) == 42);
+    
     REQUIRE_NOTHROW(lua.set_function("b", [ ] { return 42u; }));
+    REQUIRE(lua["b"](sol::types<unsigned int>()) == 42u);
+
     REQUIRE_NOTHROW(lua.set_function("c", [ ] { return 3.14; }));
+    REQUIRE(lua["c"](sol::types<double>()) == 3.14);
+
     REQUIRE_NOTHROW(lua.set_function("d", [ ] { return 6.28f; }));
+    REQUIRE(lua["d"](sol::types<float>()) == 6.28f);
+
     REQUIRE_NOTHROW(lua.set_function("e", [ ] { return "lol"; }));
+    REQUIRE(lua["e"](sol::types<std::string>()) == lol);
+
     REQUIRE_NOTHROW(lua.set_function("f", [ ] { return true; }));
+    REQUIRE(lua["f"](sol::types<bool>()));
+
     REQUIRE_NOTHROW(lua.set_function("g", [ ] { return std::string("str"); }));
+    REQUIRE(lua["g"](sol::types<std::string>()) == str);
+
     REQUIRE_NOTHROW(lua.set_function("h", [ ] { }));
+    REQUIRE_NOTHROW(lua["h"](sol::types<>()));
+    REQUIRE_THROWS(lua["h"](sol::types<int>()));
+
     REQUIRE_NOTHROW(lua.set_function("i", [ ] { return sol::nil; }));
+    REQUIRE(lua["i"](sol::types<sol::nil_t>()) == sol::nil);
+
     REQUIRE_NOTHROW(lua.set_function("j", [ ] { return std::make_tuple(1, 6.28f, 3.14, std::string( "heh" )); } ));
+    //REQUIRE(lua["j"](sol::types<int, float, double, std::string>()) == heh_tuple);
 }
 
 TEST_CASE("advanced/callLambda2", "A C++ lambda is exposed to lua and called") {