Allow IFunction::setAttribute to be overridden in Python. Refs #970

Code/Mantid/Framework/PythonInterface/inc/MantidPythonInterface/api/FitFunctions/IFunctionAdapter.h

@@ -54,8 +54,12 @@ namespace Mantid
       void declareAttribute(const std::string &name, const boost::python::object &defaultValue);
       /// Get a named attribute value
       PyObject * getAttributeValue(const std::string & name);
+      /// Returns the attribute's value as a Python object
+      PyObject * getAttributeValue(const API::IFunction::Attribute & att);
+      /// Called by the framework when an attribute has been set
+      void setAttribute(const std::string& attName,const API::IFunction::Attribute& att);
 
-      // Each overload of declareParamter requires a different name as we
+      // Each overload of declareParameter requires a different name as we
       // can't use a function pointer with a virtual base class
 
       /**

Code/Mantid/Framework/PythonInterface/mantid/api/src/Exports/IFunction.cpp

@@ -83,7 +83,8 @@ void export_IFunction()
 
     .def("declareAttribute", &IFunctionAdapter::declareAttribute, "Declare an attribute with an initial value")
 
-    .def("getAttributeValue", &IFunctionAdapter::getAttributeValue, "Return the value of the named attribute")
+    .def("getAttributeValue", (PyObject * (IFunctionAdapter::*)(const std::string &))&IFunctionAdapter::getAttributeValue,
+         "Return the value of the named attribute")
 
     .def("declareParameter", &IFunctionAdapter::declareFitParameter,
           "Declare a fitting parameter settings its default value & description")

Code/Mantid/Framework/PythonInterface/mantid/api/src/FitFunctions/IFunctionAdapter.cpp

@@ -64,25 +64,53 @@ namespace Mantid
     }
 
     /**
-     * Get the value of the given attribute as a Python object
+     * Get the value of the named attribute as a Python object
      * @param name :: The name of the new attribute
-     * @param defaultValue :: The default value for the attribute
      * @returns The value of the attribute
      */
     PyObject * IFunctionAdapter::getAttributeValue(const std::string & name)
     {
       auto attr = IFunction::getAttribute(name);
+      return getAttributeValue(attr);
+    }
+
+
+    /**
+     * Get the value of the given attribute as a Python object
+     * @param attr An attribute object
+     * @returns The value of the attribute
+     */
+    PyObject * IFunctionAdapter::getAttributeValue(const API::IFunction::Attribute & attr)
+    {
       std::string type = attr.type();
       PyObject *result(NULL);
       if(type=="int") result = to_python_value<const int&>()(attr.asInt());
       else if(type=="double") result = to_python_value<const double&>()(attr.asDouble());
       else if(type=="std::string") result = to_python_value<const std::string&>()(attr.asString());
       else if(type=="bool") result = to_python_value<const bool&>()(attr.asBool());
       else throw std::runtime_error("Unknown attribute type, cannot convert C++ type to Python. Contact developement team.");
-
       return result;
     }
 
+    /**
+     * Calls setAttributeValue on the Python object if it exists otherwise calls the base class method
+     * @param attName The name of the attribute
+     * @param attr An attribute object
+     */
+    void IFunctionAdapter::setAttribute(const std::string& attName,const Attribute& attr)
+    {
+      object value = object(handle<>(getAttributeValue(attr)));
+      try
+      {
+        CallMethod2<void,std::string,object>::dispatchWithException(getSelf(), "setAttributeValue", attName,value);
+      }
+      catch(std::runtime_error &)
+      {
+        IFunction::setAttribute(attName, attr);
+      }
+    }
+
+
     /**
      * Value of i-th active parameter. If this functions is overridden
      * in Python then it returns the value of the ith active Parameter