add nameof_enum_or

Author: Neargye

include/nameof.hpp

@@ -979,7 +979,7 @@ inline constexpr bool is_nameof_member_supported = detail::nameof_member_support
 // Checks is nameof_enum supported compiler.
 inline constexpr bool is_nameof_enum_supported = detail::nameof_enum_supported<void>::value;
 
-// Obtains simple (unqualified) name of enum variable.
+// Obtains name of enum variable.
 template <typename E>
 [[nodiscard]] constexpr auto nameof_enum(E value) noexcept -> detail::enable_if_enum_t<E, string_view> {
   using D = std::decay_t<E>;
@@ -998,11 +998,22 @@ template <typename E>
     }
   }
 
-  assert(valid && "enum variable does not have a name.");
   return {}; // Value out of range.
 }
 
-// Obtains simple (unqualified) name of enum-flags variable.
+// Obtains name of enum variable or default value if enum variable out of range.
+template <typename E>
+[[nodiscard]] auto nameof_enum_or(E value, string_view default_value) noexcept -> detail::enable_if_enum_t<E, string> {
+  using D = std::decay_t<E>;
+
+  if (auto v = nameof_enum<D>(value); !v.empty()) {
+    return string{v.data(), v.size()};
+  }
+
+  return string{default_value.data(), default_value.size()};
+}
+
+// Obtains name of enum-flags variable.
 template <typename E>
 [[nodiscard]] auto nameof_enum_flag(E value) -> detail::enable_if_enum_t<E, string> {
   using D = std::decay_t<E>;
@@ -1032,11 +1043,10 @@ template <typename E>
     return name;
   }
 
-  assert(valid && "enum-flags variable does not have a name.");
   return {}; // Invalid value or out of range.
 }
 
-// Obtains simple (unqualified) name of static storage enum variable.
+// Obtains name of static storage enum variable.
 // This version is much lighter on the compile times and is not restricted to the enum_range limitation.
 template <auto V>
 [[nodiscard]] constexpr auto nameof_enum() noexcept -> detail::enable_if_enum_t<decltype(V), string_view> {
@@ -1123,6 +1133,9 @@ template <auto V>
 // Obtains name of enum variable.
 #define NAMEOF_ENUM(...) ::nameof::nameof_enum<::std::decay_t<decltype(__VA_ARGS__)>>(__VA_ARGS__)
 
+// Obtains name of enum variable or default value if enum variable out of range.
+#define NAMEOF_ENUM_OR(...) ::nameof::nameof_enum_or(__VA_ARGS__)
+
 // Obtains name of static storage enum variable.
 // This version is much lighter on the compile times and is not restricted to the enum_range limitation.
 #define NAMEOF_ENUM_CONST(...) ::nameof::nameof_enum<__VA_ARGS__>()

test/test.cpp

@@ -107,6 +107,12 @@ struct nameof::customize::enum_range<number> {
   static_assert(max > min, "nameof::enum_range<number> requires max > min.");
 };
 
+enum class OutOfRange {
+  too_low = NAMEOF_ENUM_RANGE_MIN - 1,
+  required_to_work = 0,
+  too_high = NAMEOF_ENUM_RANGE_MAX + 1
+};
+
 struct TestRtti{
   struct Base { virtual ~Base() = default; };
   struct Derived : Base {};
@@ -442,6 +448,28 @@ TEST_CASE("NAMEOF_ENUM_FLAG") {
   NAMEOF_DEBUG_REQUIRE(NAMEOF_ENUM_FLAG(static_cast<BigFlags>((static_cast<std::uint64_t>(0x1) << 63) | 2)).empty());
 }
 
+TEST_CASE("nameof_enum_or") {
+  OutOfRange low = OutOfRange::too_low;
+  OutOfRange high = OutOfRange::too_high;
+  auto low_name = nameof::nameof_enum_or(low, "-121");
+  auto high_name = nameof::nameof_enum_or(high, "121");
+  constexpr OutOfRange oor[] = {OutOfRange::too_high, OutOfRange::too_low};
+  REQUIRE(low_name == "-121");
+  REQUIRE(high_name == "121");
+  REQUIRE(nameof::nameof_enum_or(oor[0], "121") == "121");
+}
+
+TEST_CASE("NAMEOF_ENUM_OR") {
+  OutOfRange low = OutOfRange::too_low;
+  OutOfRange high = OutOfRange::too_high;
+  auto low_name = NAMEOF_ENUM_OR(low, "-121");
+  auto high_name = NAMEOF_ENUM_OR(high, "121");
+  constexpr OutOfRange oor[] = {OutOfRange::too_high, OutOfRange::too_low};
+  REQUIRE(low_name == "-121");
+  REQUIRE(high_name == "121");
+  REQUIRE(NAMEOF_ENUM_OR(oor[0], "121") == "121");
+}
+
 #endif
 
 #if defined(NAMEOF_TYPE_SUPPORTED)