fix: deserialize

README.md

@@ -181,6 +181,33 @@ struct Outter2
 };
 ```
 
+如果你不喜欢愚蠢的侵入式函数，你可以使用 `json::serialize` 和 `json::deserialize` 进行更优雅的转换:
+
+```c++
+struct Serializer
+{
+    json::value operator()(const ThirdPartyStruct& t) const { return t.a; }
+};
+struct Deserializer
+{
+    bool operator()(const json::value& j, ThirdPartyStruct& t) const
+    {
+        if (!j.is_number()) return false;
+        t.a = j.as_integer();
+        return true;
+    }
+};
+
+std::map<std::string, ThirdPartyStruct> third;
+third["key"] = { 100 };
+json::value jthird = json::serialize(third, Serializer {});
+
+std::cout << jthird << std::endl;
+
+std::map<std::string, ThirdPartyStruct> new_third;
+bool ret = json::deserialize(jthird, new_third, Deserializer {});
+```
+
 还有一些琐碎的特性：
 
 ```c++

README_en.md

@@ -181,6 +181,33 @@ struct Outter2
 };
 ```
 
+If you don't like stupid invasive function, you can use `json::serialize` and `json::deserialize` for more elegant conversion:
+
+```c++
+struct Serializer
+{
+    json::value operator()(const ThirdPartyStruct& t) const { return t.a; }
+};
+struct Deserializer
+{
+    bool operator()(const json::value& j, ThirdPartyStruct& t) const
+    {
+        if (!j.is_number()) return false;
+        t.a = j.as_integer();
+        return true;
+    }
+};
+
+std::map<std::string, ThirdPartyStruct> third;
+third["key"] = { 100 };
+json::value jthird = json::serialize(third, Serializer {});
+
+std::cout << jthird << std::endl;
+
+std::map<std::string, ThirdPartyStruct> new_third;
+bool ret = json::deserialize(jthird, new_third, Deserializer {});
+```
+
 And some trivial features:
 
 ```c++

include/common/serialization.hpp

@@ -13,7 +13,7 @@ namespace _serialization_helper
     class is_serializable
     {
         template <typename U>
-        static auto test(int) -> decltype(std::declval<serializer_t>()(std::declval<in_t>()), std::true_type());
+        static auto test(int) -> decltype(std::declval<serializer_t>()(std::declval<U>()), std::true_type());
 
         template <typename U>
         static std::false_type test(...);
@@ -51,7 +51,7 @@ namespace _serialization_helper
     {
         template <typename U>
         static auto test(int)
-            -> decltype(std::declval<deserializer_t>()(std::declval<basic_value<string_t>>(), std::declval<out_t&>()),
+            -> decltype(std::declval<deserializer_t>()(std::declval<basic_value<string_t>>(), std::declval<U&>()),
                         std::true_type());
 
         template <typename U>
@@ -127,7 +127,7 @@ bool deserialize(const basic_value<string_t>& in, out_t& out, const deserializer
         return deserializer(in, out);
     }
     else if constexpr (std::is_constructible_v<out_t, basic_value<string_t>>) {
-        out = in;
+        out = out_t(in);
         return true;
     }
     else if constexpr (_utils::is_collection<std::decay_t<out_t>>) {

sample/sample.cpp

@@ -211,19 +211,19 @@ void third_party_jsonization_2()
     {
         bool operator()(const json::value& j, ThirdPartyStruct& t) const
         {
-            if (!j.is_number()) {
-                return false;
-            }
-
+            if (!j.is_number()) return false;
             t.a = j.as_integer();
             return true;
         }
     };
 
-    ThirdPartyStruct third;
+    std::map<std::string, ThirdPartyStruct> third;
+    third["key"] = { 100 };
     json::value jthird = json::serialize(third, Serializer {});
 
-    ThirdPartyStruct new_third;
+    std::cout << jthird << std::endl;
+
+    std::map<std::string, ThirdPartyStruct> new_third;
     bool ret = json::deserialize(jthird, new_third, Deserializer {});
 }