Restarted the production of the app

libs/CLI11/examples/enum.cpp

@@ -0,0 +1,33 @@
+// Copyright (c) 2017-2022, University of Cincinnati, developed by Henry Schreiner
+// under NSF AWARD 1414736 and by the respective contributors.
+// All rights reserved.
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+#include <CLI/CLI.hpp>
+#include <iostream>
+#include <map>
+#include <string>
+
+enum class Level : int { High, Medium, Low };
+
+int main(int argc, char **argv) {
+    CLI::App app;
+
+    Level level{Level::Low};
+    // specify string->value mappings
+    std::map<std::string, Level> map{{"high", Level::High}, {"medium", Level::Medium}, {"low", Level::Low}};
+    // CheckedTransformer translates and checks whether the results are either in one of the strings or in one of the
+    // translations already
+    app.add_option("-l,--level", level, "Level settings")
+        ->required()
+        ->transform(CLI::CheckedTransformer(map, CLI::ignore_case));
+
+    CLI11_PARSE(app, argc, argv);
+
+    // CLI11's built in enum streaming can be used outside CLI11 like this:
+    using CLI::enums::operator<<;
+    std::cout << "Enum received: " << level << std::endl;
+
+    return 0;
+}