adding config parsing

src/CMakeLists.txt

@@ -8,4 +8,11 @@ FetchContent_Declare(
 
 FetchContent_MakeAvailable(json)
 
-target_link_libraries(cppScratch PRIVATE nlohmann_json::nlohmann_json dal library)
+FetchContent_Declare(
+  Boost
+  GIT_REPOSITORY https://github.com/boostorg/boost.git
+  GIT_TAG boost-1.82.0
+)
+FetchContent_MakeAvailable(Boost)
+
+target_link_libraries(cppScratch PRIVATE nlohmann_json::nlohmann_json Boost::program_options dal library)

src/main.cpp

@@ -1,12 +1,116 @@
 #include "cppScratch/test.hpp"
 #include "cppScratch/dal/dal.hpp"
 
+#include <vector>
+#include <string>
+
 #include <nlohmann/json.hpp>
+#include <boost/program_options.hpp>
 
 using namespace std;
+namespace po = boost::program_options;
+
+void on_age(int age)
+{
+  std::cout << "On age: " << age << '\n';
+}
+
+int main(int argc, const char *argv[]) {
+    ////////////
+    // DECLARE
+    ////////////
+
+    try{
+
+        int def;
+        po::options_description desc("Allowed options");
+        desc.add_options()
+            ("help", "produce help message")
+            ("compression,c", po::value<int>(), "set compression level")
+            ("def,d", po::value<int>(&def)->default_value(10), "set def level")
+            ("abc", po::value<int>()->default_value(25), "set abc level")
+            ("phone", po::value<std::vector<std::string>>()->multitoken()->
+        zero_tokens()->composing(), "Phone")
+            ("age,a", po::value<int>()->notifier(on_age), "age")
+            ("config", po::value<std::string>(), "Config file")
+        ;
+
+        po::options_description other("Other");
+        desc.add_options()
+            ("other-option,o", po::value<int>(), "another option")
+        ;
+
+        // Hidden options, will be allowed both on command line and
+        // in config file, but will not be shown to the user.
+        po::options_description hidden("Hidden options");
+        hidden.add_options()
+            ("input-file", po::value< vector<string> >(), "input file")
+        ;  
+
+        po::positional_options_description p;
+        p.add("phone", -1);
+
+        po::options_description cmdline_options;
+        cmdline_options.add(desc).add(other).add(hidden);
+
+        po::options_description config_file_options;
+        config_file_options.add(desc).add(hidden);
+
+        po::options_description visible("Allowed options");
+        visible.add(desc).add(other);
+
+        ////////////
+        // PARSE
+        ////////////
+
+        po::variables_map vm;
+        po::store(po::command_line_parser(argc, argv)
+                .options(desc)
+                .positional(p)
+                .run(), 
+            vm);
+        if (vm.count("config"))
+        {
+            cout << "Attempting file config load" << endl;
+            std::ifstream ifs{vm["config"].as<std::string>().c_str()};
+            if (ifs) {
+                cout << "File opened, loading..." << endl;
+                po::store(po::parse_config_file(ifs, config_file_options), vm);
+            }
+        }
+        po::notify(vm);    
+
+        if (vm.count("help")) {
+            cout << desc << "\n";
+            return 1;
+        }
+
+        if (vm.count("compression")) {
+            cout << "Compression level was set to " 
+        << vm["compression"].as<int>() << ".\n";
+        } else {
+            cout << "Compression level was not set.\n";
+        }
+
+        if (vm.count("def")) {
+            cout << "def level was set to " 
+        << vm["def"].as<int>() << ".\n";
+        } else {
+            cout << "def level was not set.\n";
+        }
+
+        // if (vm.count("phone"))
+        // {
+        //     cout << "phone are: " 
+        //         << vm["phone"].as< vector<string> >() << "\n";
+        // }
 
-int main(void) {
         cout << "hello world" << endl;
         dal_func();
         example_func();
     }
+    catch (const po::error &ex)
+    {
+        std::cerr << ex.what() << '\n';
+    }
+}