Redesigned JsonVariant to leverage converting constructors instead of assignment operators

include/ArduinoJson/JsonObjectSubscript.hpp

@@ -0,0 +1,40 @@
+// Copyright Benoit Blanchon 2014-2015
+// MIT License
+//
+// Arduino JSON library
+// https://github.com/bblanchon/ArduinoJson
+
+#pragma once
+
+#include "JsonVariantBase.hpp"
+
+namespace ArduinoJson {
+class JsonObjectSubscript : public JsonVariantBase<JsonObjectSubscript> {
+ public:
+  JSON_FORCE_INLINE JsonObjectSubscript(JsonObject& object, const char* key)
+      : _object(object), _key(key) {}
+
+  JSON_FORCE_INLINE JsonObjectSubscript& operator=(const JsonVariant& value) {
+    _object.set(_key, value);
+    return *this;
+  }
+
+  JSON_FORCE_INLINE bool success() const { return _object.containsKey(_key); }
+
+  JSON_FORCE_INLINE operator JsonVariant() const { return _object.get(_key); }
+
+  template <typename T>
+  JSON_FORCE_INLINE T as() const {
+    return _object.get<T>(_key);
+  }
+
+  template <typename T>
+  JSON_FORCE_INLINE T is() const {
+    return _object.is<T>(_key);
+  }
+
+ private:
+  JsonObject& _object;
+  const char* _key;
+};
+}