#pragma once #include // int a = 1, b = 2; Cout << LabeledDump(a, b, 1 + 2); yields {"a": 1, "b": 2, "1 + 2": 3} #define LabeledDump(...) \ '{' Y_PASS_VA_ARGS(Y_MAP_ARGS_WITH_LAST(__LABELED_DUMP_NONLAST__, __LABELED_DUMP_IMPL__, __VA_ARGS__)) << '}' #define __LABELED_DUMP_IMPL__(x) << "\"" #x "\": " << DbgDump(x) #define __LABELED_DUMP_NONLAST__(x) __LABELED_DUMP_IMPL__(x) << ", " // Usage: struct TMyStruct { int A, B; }; DEFINE_DUMPER(TMyStruct, A, B); Cout << TMyStruct{3, 4}; // yields {"A": 3, "B": 4} #define DEFINE_DUMPER(C, ...) \ template <> \ struct TDumper { \ template \ static inline void Dump(S& s, const C& v) { \ s << DumpRaw("{") Y_PASS_VA_ARGS(Y_MAP_ARGS_WITH_LAST(__DEFINE_DUMPER_NONLAST__, __DEFINE_DUMPER_IMPL__, __VA_ARGS__)) << DumpRaw("}"); \ } \ }; #define __DEFINE_DUMPER_IMPL__(x) << DumpRaw("\"" #x "\": ") << v.x #define __DEFINE_DUMPER_NONLAST__(x) __DEFINE_DUMPER_IMPL__(x) << DumpRaw(", ")