deploy: 4155e2938f

examples/json_editable_document.cpp

@@ -0,0 +1,30 @@
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json = nlohmann::json;
+using json_editable_document = nlohmann::json_editable_document;
+using json_editable_view = nlohmann::json_editable_view;
+
+int main()
+{
+    // a configuration file, as it might be read from disk
+    const std::string text = R"({"name": "cache", "host": "db1", "port": 6379, "price": 19.90})";
+    std::cout << text << "\n\n";
+
+    // patch two fields -- "price" is never touched
+    json_editable_document doc = json_editable_document::parse(text);
+    doc.set(doc.root(), "host", "db2");
+    doc.set(doc.root(), "retries", 3);
+
+    // member order (the new member at the end) and the untouched number's
+    // exact spelling survive
+    std::cout << doc.root().dump(-1, ' ', false, json_editable_view::number_format::source) << '\n';
+
+    // the same patch on a plain json value: keys are sorted (object_t is a
+    // std::map), and "price" is rewritten even though the patch never
+    // touched it
+    json plain = json::parse(text);
+    plain["host"] = "db2";
+    plain["retries"] = 3;
+    std::cout << plain.dump() << '\n';
+}