Adding fail if required values missing

examples/simple.cpp

@@ -8,7 +8,10 @@ int main(int argc, char **argv) {
     CLI::Option *opt = app.add_option("-f,--file,file", file, "File name");
 
     int count;
-    CLI::Option *copt = app.add_flag("-c,--count", count, "Counter");
+    CLI::Option *copt = app.add_option("-c,--count", count, "Counter");
+
+    int v;
+    CLI::Option *flag = app.add_flag("--flag", v, "Some flag that can be passed multiple times");
 
     double value; // = 3.14;
     app.add_option("-d,--double", value, "Some Value");
@@ -19,6 +22,7 @@ int main(int argc, char **argv) {
               << ", opt count: " << opt->count() << std::endl;
     std::cout << "Working on count: " << count << ", direct count: " << app.count("--count")
               << ", opt count: " << copt->count() << std::endl;
+    std::cout << "Recieved flag: " << v << " (" << flag->count() << ") times\n";
     std::cout << "Some value: " << value << std::endl;
 
     return 0;

include/CLI/App.hpp

@@ -1196,7 +1196,9 @@ class App {
             if(num_left_over > 0) {
                 args = remaining(false);
                 std::reverse(std::begin(args), std::end(args));
-                throw ExtrasError("[" + detail::rjoin(args, " ") + "]");
+                throw ExtrasError((args.size() > 1 ? "The following argument was not expected: "
+                                                   : "The following arguments were not expected: ") +
+                                  detail::rjoin(args, " "));
             }
         }
     }
@@ -1415,7 +1417,7 @@ class App {
                 args.pop_back();
                 already_ate_one = true;
             }
-        } else
+        } else {
             while(num > 0 && !args.empty()) {
                 num--;
                 std::string current_ = args.back();
@@ -1424,6 +1426,12 @@ class App {
                 parse_order_.push_back(op.get());
             }
 
+            if(num > 0) {
+                throw RequiredError(op->single_name() + ": " + std::to_string(num) + " required " +
+                                    op->get_type_name() + " missing");
+            }
+        }
+
         if(!rest.empty()) {
             rest = "-" + rest;
             args.push_back(rest);
@@ -1499,6 +1507,10 @@ class App {
                 parse_order_.push_back(op.get());
                 args.pop_back();
             }
+            if(num > 0) {
+                throw RequiredError(op->single_name() + ": " + std::to_string(num) + " required " +
+                                    op->get_type_name() + " missing");
+            }
         }
         return;
     }

include/CLI/Option.hpp

@@ -551,6 +551,9 @@ class Option : public OptionBase<Option> {
     /// Set the type name displayed on this option
     void set_type_name(std::string val) { typeval_ = val; }
 
+    /// Get the typename for this option
+    std::string get_type_name() const { return typeval_; }
+
     ///@}
 
   protected:

tests/AppTest.cpp

@@ -230,6 +230,19 @@ TEST_F(TApp, TakeLastOpt) {
     EXPECT_EQ(str, "two");
 }
 
+TEST_F(TApp, MissingValueNonRequiredOpt) {
+    int count;
+    app.add_option("-c,--count", count);
+
+    args = {"-c"};
+    EXPECT_ANY_THROW(run());
+
+    app.reset();
+
+    args = {"--count"};
+    EXPECT_ANY_THROW(run());
+}
+
 TEST_F(TApp, RequiredOptsSingle) {
 
     std::string str;
@@ -1189,7 +1202,7 @@ TEST_F(TApp, OrderedModifingTransforms) {
 TEST_F(TApp, ThrowingTransform) {
     std::string val;
     auto m = app.add_option("-m,--mess", val);
-    m->transform([](std::string x) -> std::string { throw CLI::ValidationError("My Message"); });
+    m->transform([](std::string) -> std::string { throw CLI::ValidationError("My Message"); });
 
     EXPECT_NO_THROW(run());
     app.reset();

tests/NewParseTest.cpp

@@ -91,5 +91,5 @@ TEST_F(TApp, BuiltinComplexFail) {
 
     args = {"-c", "4"};
 
-    EXPECT_THROW(run(), CLI::ConversionError);
+    EXPECT_THROW(run(), CLI::RequiredError);
 }