Report better errors if options are missing args

src/option.cc

@@ -194,8 +194,8 @@ strings_list process_arguments(strings_list args, scope_t& scope)
       if (! opt.first)
 	throw_(option_error, "illegal option --" << name);
 
-      if (opt.second && value == NULL) {
+      if (opt.second && ++i != args.end() && value == NULL) {
-	value = (*++i).c_str();
+	value = (*i).c_str();
 	DEBUG("option.args", "  read option value from arg: " << value);
 	if (value == NULL)
 	  throw_(option_error, "missing option argument for --" << name);
@@ -222,8 +222,8 @@ strings_list process_arguments(strings_list args, scope_t& scope)
 
       foreach (op_bool_char_tuple& o, option_queue) {
 	const char * value = NULL;
-	if (o.truth) {
+	if (o.truth && ++i != args.end()) {
-	  value = (*++i).c_str();
+	  value = (*i).c_str();
 	  DEBUG("option.args", "  read option value from arg: " << value);
 	  if (value == NULL)
 	    throw_(option_error,

src/option.h

@@ -90,10 +90,17 @@ public:
 
   string desc() const {
     std::ostringstream out;
+    out << "--";
+    for (const char * p = name; *p; p++) {
+      if (*p == '_') {
+	if (*(p + 1))
+	  out << '-';
+      } else {
+	out << *p;
+      }
+    }
     if (ch)
-      out << "--" << name << " (-" << ch << ")";
+      out << " (-" << ch << ")";
-    else
-      out << "--" << name;
     return out.str();
   }
 
@@ -136,10 +143,13 @@ public:
   virtual void handler_thunk(call_scope_t&) {}
 
   virtual void handler(call_scope_t& args) {
-    if (wants_arg)
+    if (wants_arg) {
+      if (args.empty())
+	throw_(std::runtime_error, "No argument provided for " << desc());
       on(args[0]);
-    else
+    } else {
       on();
+    }
 
     handler_thunk(args);
   }