cmdopt: add bool value option specialisation

cmdopt.cpp

@@ -162,6 +162,48 @@ present::finish (void)
 }
 
 
+///////////////////////////////////////////////////////////////////////////////
+namespace util { namespace cmdopt { namespace option {
+    template <>
+    void
+    value<bool>::execute (const char *restrict str)
+    {
+        static const std::string TRUE_STRING[] = {
+            "true",
+            "yes",
+            "y",
+            "1"
+        };
+
+        if (std::any_of (std::begin (TRUE_STRING),
+                         std::end (TRUE_STRING),
+                         [str] (auto i) { return i == str; }))
+        {
+            m_data = true;
+            return;
+        }
+
+        static const std::string FALSE_STRING[] = {
+            "false",
+            "no",
+            "n",
+            "0"
+        };
+
+        if (std::any_of (std::begin (FALSE_STRING),
+                         std::end (FALSE_STRING),
+                         [str] (auto i) { return i == str; }))
+        {
+            m_data = false;
+            return;
+        }
+
+        base::execute (str);
+        seen (true);
+    }
+} } }
+
+
 //-----------------------------------------------------------------------------
 namespace util { namespace cmdopt { namespace option {
     template class value<uint16_t>;