Added attribute isSet()

VirtualRobot/CMakeLists.txt

@@ -518,6 +518,7 @@ SET(INCLUDES
     MJCF/elements/has_member.hpp
     MJCF/elements/core/AnyElement.h
     MJCF/elements/core/Attribute.h
+    MJCF/elements/core/const_aware_ptr.hpp
     MJCF/elements/core/Element.h
     MJCF/elements/core/exceptions.h
     MJCF/elements/core/mjcf_utils.h

VirtualRobot/MJCF/elements/core/Attribute.h

@@ -101,6 +101,9 @@ namespace mjcf
         /// Indicate whether the attribute has a default (implies optional).
         virtual bool hasDefault() const = 0;
         
+        /// Indicate whether the attribute is set.
+        bool isSet() const { return this->owner().isAttributeSet(this->name); }
+        
         
     protected:
         
@@ -181,6 +184,7 @@ namespace mjcf
     private:
         
         AttrT defaultValue; ///< The default value.
+        
     };