Add a comment to unify the UFCS macro once all compilers support it, closes #46

Author: hsutter

include/cpp2util.h

@@ -458,6 +458,23 @@ class out {
 //
 //-----------------------------------------------------------------------
 //
+
+//--------------------------------------------------------------------
+//  TODO: When MSVC supports __VA_OPT__ in standard mode without the
+//        experimental /Zc:preprocessor switch, use this single macro
+//        instead of the dual macros below that special-case _0 args
+//  AND:  Make the similarly noted change in cppfront.cpp
+//
+//#define CPP2_UFCS(FUNCNAME,PARAM1,...) \
+//[](auto&& obj __VA_OPT__(, auto&& ...params) ) { \
+//    if constexpr (requires{ std::forward<decltype(obj)>(obj).FUNCNAME(__VA_OPT__(std::forward<decltype(params)>(params)...)); }) { \
+//        return std::forward<decltype(obj)>(obj).FUNCNAME(__VA_OPT__(std::forward<decltype(params)>(params)...)); \
+//    } else { \
+//        return FUNCNAME(std::forward<decltype(obj)>(obj) __VA_OPT__(, std::forward<decltype(params)>(params)...)); \
+//    } \
+//}(PARAM1 __VA_OPT__(, __VA_ARGS__) )
+
+
 #define CPP2_UFCS(FUNCNAME,PARAM1,...) \
 [](auto&& obj, auto&& ...params) { \
     if constexpr (requires{ std::forward<decltype(obj)>(obj).FUNCNAME(std::forward<decltype(params)>(params)...); }) { \
@@ -475,6 +492,7 @@ class out {
         return FUNCNAME(std::forward<decltype(obj)>(obj)); \
     } \
 }(PARAM1)
+//--------------------------------------------------------------------
 
 
 //-----------------------------------------------------------------------

source/cppfront.cpp

@@ -1630,13 +1630,22 @@ class cppfront
             //  The ( has its expr_list and op_close
             assert (n.ops[1].expr_list && n.ops[1].op_close);
 
+            //--------------------------------------------------------------------
+            //  TODO: When MSVC supports __VA_OPT__ in standard mode without the
+            //        experimental /Zc:preprocessor switch, use this single line
+            //        instead of the dual lines below that special-case _0 args
+            //  AND:  Make the similarly noted change in cpp2util.h
+            //
+            //printer.print_cpp2("CPP2_UFCS(", n.position());
+
             //  If there are no additional arguments, use the CPP2_UFCS_0 version
             if (!n.ops[1].expr_list->expressions.empty()) {
                 printer.print_cpp2("CPP2_UFCS(", n.position());
             }
             else {
                 printer.print_cpp2("CPP2_UFCS_0(", n.position());
             }
+            //--------------------------------------------------------------------
 
             //  Make the "funcname" the first argument to CPP2_UFCS
             emit(*n.ops[0].id_expr);