Add benchmark

* add benchmark option
* updated changelog
* added benchmark info to readme
* add bench folder to format.py

bench/main.cpp

@@ -0,0 +1,63 @@
+/*
+ * This project is licensed under the MIT license. For more information see the
+ * LICENSE file.
+ */
+#include <fstream>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+
+#define ANKERL_NANOBENCH_IMPLEMENT
+#include <nanobench.h>
+
+#include "maddy/parser.h"
+
+int main()
+{
+  static const std::string markdownFile = "../docs/definitions.md";
+  std::stringstream buffer;
+
+  {
+    std::ifstream file(markdownFile);
+
+    if (!file.good() || !file.is_open())
+    {
+      std::cout << "could not read file at " << markdownFile << std::endl;
+      return 1;
+    }
+
+    buffer << file.rdbuf();
+
+    file.close();
+  }
+
+  if (!buffer.good() || buffer.str().empty())
+  {
+    std::cout << "buffer is invalid" << std::endl;
+    return 2;
+  }
+
+  // maddy 1.*
+  std::shared_ptr<maddy::Parser> parser = std::make_shared<maddy::Parser>();
+
+  // This is the place in the future to compare maddy with other libraries.
+  // For now it can be used to check if changes in maddy code result in better
+  // performance.
+
+  ankerl::nanobench::Bench()
+    .title("maddy test")
+    .warmup(100)
+    .relative(true)
+    .run(
+      "maddy 1.x",
+      [&]()
+      {
+        buffer.clear(); // clear any error flags
+        buffer.seekg(0, buffer.beg);
+        ankerl::nanobench::doNotOptimizeAway(parser->Parse(buffer));
+      }
+    );
+
+  return 0;
+}