cleanup, test, and diff

README.md

@@ -428,7 +428,7 @@ $ make
 $ ./json_unit "*"
 
 ===============================================================================
-All tests passed (3344416 assertions in 30 test cases)
+All tests passed (3344554 assertions in 31 test cases)
 ```
 
 For more information, have a look at the file [.travis.yml](https://github.com/nlohmann/json/blob/master/.travis.yml).

doc/examples/diff.cpp

+#include <json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // the source document
+    json source = R"(
+        {
+            "baz": "qux",
+            "foo": "bar"
+        }
+    )"_json;
+
+    // the target document
+    json target = R"(
+        {
+            "baz": "boo",
+            "hello": [
+                "world"
+            ]
+        }
+    )"_json;
+
+    // create the patch
+    json patch = json::diff(source, target);
+
+    // roundtrip
+    json patched_source = source.patch(patch);
+
+    // output patch and roundtrip result
+    std::cout << std::setw(4) << patch << "\n\n"
+              << std::setw(4) << patched_source << std::endl;
+}

doc/examples/diff.link

+<a target="_blank" href="http://melpon.org/wandbox/permlink/hicmeOK39tBxaluM"><b>online</b></a>
\ No newline at end of file

doc/examples/diff.output

+[
+    {
+        "op": "replace",
+        "path": "/baz",
+        "value": "boo"
+    },
+    {
+        "op": "remove",
+        "path": "/foo"
+    },
+    {
+        "op": "add",
+        "path": "/hello",
+        "value": [
+            "world"
+        ]
+    }
+]
+
+{
+    "baz": "boo",
+    "hello": [
+        "world"
+    ]
+}

doc/examples/patch.cpp

+#include <json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // the original document
+    json doc = R"(
+        {
+          "baz": "qux",
+          "foo": "bar"
+        }
+    )"_json;
+
+    // the patch
+    json patch = R"(
+        [
+          { "op": "replace", "path": "/baz", "value": "boo" },
+          { "op": "add", "path": "/hello", "value": ["world"] },
+          { "op": "remove", "path": "/foo"}
+        ]
+    )"_json;
+
+    // apply the patch
+    json patched_doc = doc.patch(patch);
+
+    // output original and patched document
+    std::cout << std::setw(4) << doc << "\n\n"
+              << std::setw(4) << patched_doc << std::endl;
+}

doc/examples/patch.link

+<a target="_blank" href="http://melpon.org/wandbox/permlink/lbczW3AzcUbH1Nbo"><b>online</b></a>
\ No newline at end of file

doc/examples/patch.output

+{
+    "baz": "qux",
+    "foo": "bar"
+}
+
+{
+    "baz": "boo",
+    "hello": [
+        "world"
+    ]
+}