using std::optional in favor of bool return

include/vsg/core/Object.h

@@ -14,6 +14,7 @@ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLI
 
 #include <atomic>
 #include <string>
+#include <optional>
 
 #include <vsg/core/Export.h>
 #include <vsg/core/ref_ptr.h>
@@ -76,7 +77,7 @@ namespace vsg
         void setValue(const std::string& key, const char* value) { setValue(key, value ? std::string(value) : std::string()); }
 
         template<typename T>
-        bool getValue(const std::string& key, T& value) const;
+        std::optional<T> getValue(const std::string& key) const;
 
         void setObject(const std::string& key, Object* object);
         Object* getObject(const std::string& key);

include/vsg/core/Value.h

@@ -106,19 +106,18 @@ namespace vsg
     }
 
     template<typename T>
-    bool Object::getValue(const std::string& key, T& value) const
+    std::optional<T> Object::getValue(const std::string& key) const
     {
         using ValueT = Value<T>;
         const Object* object = getObject(key);
         if (object && (typeid(*object) == typeid(ValueT)))
         {
             const ValueT* vo = static_cast<const ValueT*>(getObject(key));
-            value = *vo;
-            return true;
+            return *vo;
         }
         else
         {
-            return false;
+            return {};
         }
     }
 

src/vsg/io/ObjectFactory.cpp

@@ -30,7 +30,7 @@ using namespace vsg;
 
 ObjectFactory::ObjectFactory()
 {
-    _createMap["nulltr"] = []() { return ref_ptr<Object>(); };
+    _createMap["nullptr"] = []() { return ref_ptr<Object>(); };
 
     VSG_REGISTER_new(vsg::Object);