added option -h and -v

ml.cpp

@@ -1773,7 +1773,20 @@ MlValue MlEnvironment::get(const std::string &name) const {
 	throw MlError(MlValue::atom(name), *this, ATOM_NOT_DEFINED);
 }
 
-int main(int argc, const char **argv) {
+std::vector<std::string> getCmdOption(char *argv[], int argc, const std::string &option) {
+	std::vector<std::string> tokens;
+	for (int i = 1; i < argc; ++i) {
+		if (option == argv[i] && i + 1 < argc) {
+			i++;
+			tokens.push_back(std::string(argv[i]));
+		}
+	}
+	return tokens;
+}
+
+bool cmdOptionExists(char **begin, char **end, const std::string &option) { return std::find(begin, end, option) != end; }
+
+int main(int argc, char *argv[]) {
 	MlEnvironment env;
 	std::vector<MlValue> args;
 	for (int i = 0; i < argc; i++)
@@ -1786,6 +1799,18 @@ int main(int argc, const char **argv) {
         // for xcode profiling
         // run(read_file_contents("/Users/vaclavt/Development/mlisp/tests/test.lsp"), env);
 
+	// help
+	if (cmdOptionExists(argv, argv + argc, "-h")) {
+		std::cout << "Usage:\n\t-h print this help\n\t-f source_file - executes code in file\n\t-c code - runs passed code\n\t-i runs repl\n\t-v prints version string\n\n";
+		return 0;
+	}
+
+	// version
+	if (cmdOptionExists(argv, argv + argc, "-v")) {
+		std::cout << VERSION << std::endl;
+		return 0;
+	}
+
 		if (argc == 1 || (argc == 2 && std::string(argv[1]) == "-i"))
 			repl(env);
 		else if (argc == 3 && std::string(argv[1]) == "-c")