cmdopt: add null option

cmdopt.cpp

@@ -117,6 +117,28 @@ base::seen (bool _seen)
 
 
 ///////////////////////////////////////////////////////////////////////////////
+null::null (std::string _name):
+    base (std::move (_name))
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+void
+null::execute (void)
+{
+    seen (true);
+}
+
+
+//-----------------------------------------------------------------------------
+void
+null::execute (const char *restrict)
+{
+    seen (true);
+}
+
+
+//-----------------------------------------------------------------------------
 namespace util { namespace cmdopt { namespace option {
     template class value<uint16_t>;
     template class value<uint32_t>;

cmdopt.hpp

@@ -51,6 +51,15 @@ namespace util { namespace cmdopt {
         };
 
 
+        class null : public base {
+        public:
+            null (std::string name);
+
+            virtual void execute (void) override;
+            virtual void execute (const char *restrict) override;
+        };
+
+
         template <typename T>
         class value : public base {
         public: