chore: 整理MEO_OPT及文档

MistEO · Jan 24, 2024 · 9c007b5 · 9c007b5
1 parent 1e45d6f
commit 9c007b5
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Showing 4 changed files with 26 additions and 63 deletions.
diff --git a/README.md b/README.md
@@ -271,24 +271,29 @@ void test_jsonization()
         double d = 0;
 
         // 如果你正在使用 MSVC, 请添加 "/Zc:preprocessor" 到项目设置中
-        MEO_JSONIZATION(vec, map, i, d);
+        MEO_JSONIZATION(vec, map, MEO_OPT i, d);
     };
 
     MyStruct a;
-    a.vec = { 1, 2, 3, 4, 5 };
+    a.vec = { 1, 2, 3 };
     a.map = { { "key", 5 } };
     a.i = 100;
     a.d = 0.5;
 
-    json::object j = a.dump_to_json();
+    json::object dumps = a.to_json();
 
     // output: { "d" : 0.500000, "i" : 100, "map" : { "key" : 5 }, "vec" : [ 1, 2, 3 ] }
-    std::cout << j << std::endl;
+    std::cout << dumps << std::endl;
+
+    // MEO_OPT 表示该变量是一个可选项
+    // 即使输入中不存在该字段依然可以读取
+    dumps.erase("i")
 
     MyStruct b;
-    b.load_from_json(j);
+    b.from_json(dumps);
 
-    // output: { "d" : 0.500000, "i" : 100, "map" : { "key" : 5 }, "vec" : [ 1, 2, 3 ] }
-    std::cout << b.dump_to_json() << std::endl;
+    // output: { "d" : 0.500000, "i" : 0, "map" : { "key" : 5 }, "vec" : [ 1, 2, 3 ] }
+    // 我们从 dumps 中删除了 "i", 所以 "i" 是 0
+    std::cout << b.to_json() << std::endl;
 }
 ```
diff --git a/README_en.md b/README_en.md
@@ -271,24 +271,29 @@ void test_jsonization()
         double d = 0;
 
         // if you are using MSVC, please add "/Zc:preprocessor" to your project
-        MEO_JSONIZATION(vec, map, i, d);
+        MEO_JSONIZATION(vec, map, MEO_OPT i, d);
     };
 
     MyStruct a;
-    a.vec = { 1, 2, 3, 4, 5 };
+    a.vec = { 1, 2, 3 };
     a.map = { { "key", 5 } };
     a.i = 100;
     a.d = 0.5;
 
-    json::object j = a.dump_to_json();
+    json::object dumps = a.to_json();
 
     // output: { "d" : 0.500000, "i" : 100, "map" : { "key" : 5 }, "vec" : [ 1, 2, 3 ] }
-    std::cout << j << std::endl;
+    std::cout << dumps << std::endl;
+
+    // MEO_OPT means the var is optional
+    // and can still be read even if the field doesn't exist in the input.
+    dumps.erase("i")
 
     MyStruct b;
-    b.load_from_json(j);
+    b.from_json(dumps);
 
-    // output: { "d" : 0.500000, "i" : 100, "map" : { "key" : 5 }, "vec" : [ 1, 2, 3 ] }
-    std::cout << b.dump_to_json() << std::endl;
+    // output: { "d" : 0.500000, "i" : 0, "map" : { "key" : 5 }, "vec" : [ 1, 2, 3 ] }
+    // "i" is 0 because we erase "i" from the dumps
+    std::cout << b.to_json() << std::endl;
 }
 ```
diff --git a/include/json.hpp b/include/json.hpp
@@ -2779,49 +2779,6 @@ static constexpr string_t unescape_string(const string_t& str)
 
     return result;
 }
-
-namespace _jsonization_helper
-{
-    struct required_tag
-    {
-        constexpr static bool required = true;
-    };
-    struct optional_tag
-    {
-        constexpr static bool required = false;
-    };
-}
-
-struct bind_helper
-{
-    void __to_json(json::object&) const {}
-
-    bool __from_json(const json::object&) { return true; }
-
-    template <typename Tag, typename Var, typename... Rest>
-    void __to_json(json::object& obj, Tag, const Var& var, const char* name, Rest&&... rest) const
-    {
-        obj[name] = json::serialize<false>(var);
-        __to_json(obj, std::forward<Rest>(rest)...);
-    }
-
-    template <typename Tag, typename Var, typename... Rest>
-    bool __from_json(const json::object& raw, Tag, Var& var, const char* name, Rest&&... rest)
-    {
-        if (auto opt = raw.find(name)) {
-            if (!opt->is<Var>()) {
-                return false;
-            }
-            var = std::move(opt)->as<Var>();
-        }
-        else {
-            if constexpr (Tag::required) {
-                return false;
-            }
-        }
-        return __from_json(raw, std::forward<Rest>(rest)...);
-    }
-};
 } // namespace json
 
 namespace json::_jsonization_helper
@@ -2837,7 +2794,7 @@ class dumper
     template <typename var_t, typename... rest_t>
     json::object to_json(const char* key, const var_t& var, rest_t&&... rest) const
     {
-        auto result = to_json(std::forward<rest_t>(rest)...);
+        json::object result = to_json(std::forward<rest_t>(rest)...);
         if constexpr (!std::is_same_v<next_is_optional_t, var_t>) {
             result.emplace(key, json::serialize<false>(var));
         }
@@ -2989,10 +2946,6 @@ namespace json::_private_macro
         return json::_jsonization_helper::loader().from_json(_MEOJSON_VARNAME(in), _MEOJSON_VARNAME(error_key), \
                                                              _MEOJSON_FOR_EACH(_MEOJSON_KEY_VALUE, __VA_ARGS__) \
                                                                  json::_jsonization_helper::va_arg_end());      \
-    }                                                                                                           \
-    explicit operator json::object() const                                                                      \
-    {                                                                                                           \
-        return to_json();                                                                                       \
     }
 
 #define MEO_OPT json::_jsonization_helper::next_is_optional_t {},
diff --git a/sample/sample.cpp b/sample/sample.cpp
@@ -326,7 +326,7 @@ void test_jsonization()
     json::object j = a.to_json();
     std::cout << j << std::endl;
 
-    // for test MEO_OPTIONAL
+    // for test MEO_OPT
     j.erase("i");
 
     MyStruct b;