cmdopt: add present option

cmdopt.cpp

@@ -138,6 +138,30 @@ null::execute (const char *restrict)
 }
 
 
+///////////////////////////////////////////////////////////////////////////////
+present::present (std::string _name, bool &_data):
+    base (std::move (_name)),
+    m_data (_data)
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+void
+present::execute (void)
+{
+    seen (true);
+}
+
+
+//-----------------------------------------------------------------------------
+void
+present::finish (void)
+{
+    m_data = seen ();
+    base::finish ();
+}
+
+
 //-----------------------------------------------------------------------------
 namespace util { namespace cmdopt { namespace option {
     template class value<uint16_t>;

cmdopt.hpp

@@ -60,6 +60,20 @@ namespace util { namespace cmdopt {
         };
 
 
+        class present : public base {
+        public:
+            present (std::string name, bool&);
+
+            using base::execute;
+            virtual void execute (void) override;
+
+            virtual void finish (void) override;
+
+        private:
+            bool &m_data;
+        };
+
+
         template <typename T>
         class value : public base {
         public: