Avoid injecting template to adl

include/xcpp/xdisplay.hpp

@@ -19,34 +19,32 @@ namespace nl = nlohmann;
 namespace xcpp
 {
     template <class T>
-    void display(const T& t)
+    void display(T&& t)
     {
-        using ::xcpp::mime_bundle_repr;
         xeus::get_interpreter().display_data(
-            mime_bundle_repr(t),
+            dispatch_mime_bundle_repr(std::forward<T>(t)),
             nl::json::object(),
             nl::json::object()
         );
     }
 
     template <class T>
-    void display(const T& t, xeus::xguid id, bool update=false)
+    void display(T&& t, xeus::xguid id, bool update=false)
     {
         nl::json transient;
         transient["display_id"] = id;
-        using ::xcpp::mime_bundle_repr;
         if (update)
         {
             xeus::get_interpreter().update_display_data(
-                mime_bundle_repr(t),
+                dispatch_mime_bundle_repr(std::forward<T>(t)),
                 nl::json::object(),
                 std::move(transient)
             );
         }
         else
         {
             xeus::get_interpreter().display_data(
-                mime_bundle_repr(t),
+                dispatch_mime_bundle_repr(std::forward<T>(t)),
                 nl::json::object(),
                 std::move(transient)
             );

include/xcpp/xmime.hpp

@@ -12,6 +12,7 @@
 
 #include <complex>
 #include <sstream>
+#include <type_traits>
 
 #include "nlohmann/json.hpp"
 
@@ -39,11 +40,14 @@ namespace xcpp
             return bundle;
         }
 
+        // Helper struct for SFINAE concept check - obsolete with C++17
+        template<class...>
+        using void_t = void;
     }
 
     // Default implementation of mime_bundle_repr
     template <class T>
-    nl::json mime_bundle_repr(const T& value)
+    nl::json fallback_mime_bundle_repr(const T& value)
     {
         auto bundle = nl::json::object();
         bundle["text/plain"] = cling::printValue(&value);
@@ -52,17 +56,41 @@ namespace xcpp
 
     // Implementation for std::complex.
     template <class T>
-    nl::json mime_bundle_repr(const std::complex<T>& value)
+    nl::json fallback_mime_bundle_repr(const std::complex<T>& value)
     {
         return detail::mime_bundle_repr_via_sstream(value);
     }
 
     // Implementation for long double. This is a workaround for
     // https://github.com/jupyter-xeus/xeus-cling/issues/220
-    inline nl::json mime_bundle_repr(const long double& value)
+    inline nl::json fallback_mime_bundle_repr(const long double& value)
     {
         return detail::mime_bundle_repr_via_sstream(value);
     }
+
+    template<typename T, typename = void>
+    struct MimeBundleReprDispatcher
+    {
+        template<typename U>
+        static nl::json dispatch(U&& u) {
+            return fallback_mime_bundle_repr(std::forward<U>(u));
+        }
+    };
+
+    template<typename T>
+    struct MimeBundleReprDispatcher<T, detail::void_t<decltype(mime_bundle_repr(std::declval<T>()))>>
+    {
+        template<typename U>
+        static nl::json dispatch(U&& u) {
+            return mime_bundle_repr(std::forward<U>(u));
+        }
+    };
+
+    template<typename T>
+    nl::json dispatch_mime_bundle_repr(T&& t)
+    {
+        return MimeBundleReprDispatcher<T>::dispatch(std::forward<T>(t));
+    }
 }
 
 #endif

src/xmime_internal.hpp

@@ -191,8 +191,7 @@ namespace xcpp
         {
             // Use an llvm::raw_ostream to prepend '0x' in front of the pointer value.
             cling::ostrstream code;
-            code << "using xcpp::mime_bundle_repr;";
-            code << "mime_bundle_repr(";
+            code << "xcpp::dispatch_mime_bundle_repr(";
             code << "*(" << xcpp::cling_detail::getTypeString(V);
             code << &value;
             code << "));";