cli parsing

src/main.cpp

@@ -1,40 +1,69 @@
 #include <boost/program_options.hpp>
+#include <boost/program_options/parsers.hpp>
+#include <boost/program_options/positional_options.hpp>
+#include <boost/program_options/variables_map.hpp>
 
+#include <exception>
 #include <iostream>
 
 #include "graphics.hpp"
 
 namespace po = boost::program_options;
+using namespace std;
+
+int main(int argc, char **argv);
+
+void help(char *prog, po::options_description desc);
 
 int main(int argc, char **argv) {
 
-  printf("argc:\t\t%d\n", argc);
+  /* Parsing CLI Arguments */
-  for (int i = 0; i < argc; i++) {
+  po::options_description desc("Available options");
-    printf("argv[%d]:\t%s\n", i, argv[i]);
+  desc.add_options()
-  }
+    ("help,h", "show help")
-  std::cout << std::endl;
+    ("verbose,v", "more verbose output")
+    ("vert", po::value<string>()->required(), "vertex shader file")
+    ("frag", po::value<string>()->required(), "fragment shader file");
 
-  po::options_description desc("Allowed options");
+  /* unused for now */
-  desc.add_options()("help", "produce help message")(
+  po::positional_options_description pdesc;
-      "compression", po::value<int>(), "set compression level");
+  // NOTE: if you want to add a positional argument,
+  // you need to create and option for it as it seems.
+  pdesc.add("vert", 1);
+  pdesc.add("frag", 1);
 
   po::variables_map vm;
-  /* po::store(po::parse_command_line(ac, av, desc), vm); */
+  try {
-  po::notify(vm);
 
-  if (vm.count("help")) {
+    po::store(po::command_line_parser(argc, argv)
-    std::cout << desc << "\n";
+                  .options(desc)     // load options
+                  .positional(pdesc) // load positionals
+                  .run(),
+              vm);
+    po::notify(vm);
+    if (vm.count("help") || argc < 3) {
+      help(argv[0], desc);
+      return 1;
+    }
+  } catch (po::error &e) {
+    cout << e.what() << endl << endl;
+    help(argv[0], desc);
     return 1;
   }
 
-  if (vm.count("compression")) {
+  if (vm.count("verbose")) {
-    std::cout << "Compression level was set to " << vm["compression"].as<int>()
+    printf("verbose!");
-              << ".\n";
-  } else {
-    std::cout << "Compression level was not set.\n";
   }
 
+  /* Run our main program */
   int result = mainWindow();
 
   return result;
 }
+
+void help(char *prog, po::options_description desc) {
+  cout << "Usage:" << endl
+       << prog << " [-vh] [--vert] shaders/vertex.glsl [--frag] shaders/fragment.glsl"
+       << endl << endl
+       << desc << endl;
+}