Add nested structure case

Author: Yaraslaut

include/reflection-cpp/reflection.hpp

@@ -361,6 +361,9 @@ namespace detail
         (f.template operator()<Xs>(), ...);
     }
 
+    template <typename T>
+    constexpr bool can_be_formatted = std::is_arithmetic_v<T> || std::is_convertible_v<T, std::string>;
+
 } // namespace detail
 
 template <auto B, auto E, typename F>
@@ -433,9 +436,17 @@ std::string Inspect(Object const& object)
             if constexpr (std::is_convertible_v<T, std::string>
                        || std::is_convertible_v<T, std::string_view>
                        || std::is_convertible_v<T, char const*>) // clang-format on
+            {
                 str += std::format("\"{}\"", arg);
-            else
+            }
+            else if constexpr (std::is_convertible_v<T, int>) // use std::formattable when available
+            {
                 str += std::format("{}", arg);
+            }
+            else
+            {
+                str += Inspect(arg);
+            }
         };
         if (!str.empty())
             str += ' ';

test-reflection-cpp.cpp

@@ -3,6 +3,7 @@
 
 #include <catch2/catch_test_macros.hpp>
 
+#include <iostream>
 #include <string>
 #include <string_view>
 
@@ -13,6 +14,15 @@ struct Person
     int age;
 };
 
+struct TestStruct
+{
+    int a;
+    float b;
+    double c;
+    std::string d;
+    Person e;
+};
+
 enum Color
 {
     Red,
@@ -39,3 +49,10 @@ TEST_CASE("core", "[reflection]")
     auto const result = Reflection::Inspect(p);
     CHECK(result == R"(name="John Doe" email="[email protected]" age=42)");
 }
+
+TEST_CASE("nested", "[reflection]")
+{
+    auto ts = TestStruct { 1, 2.0f, 3.0, "hello", { "John Doe", "[email protected]", 42 } };
+    auto const result = Reflection::Inspect(ts);
+    CHECK(result == R"(a=1 b=2 c=3 d="hello" e=name="John Doe" email="[email protected]" age=42)");
+}