code: public ValueList getValues(PDefinition def, ObjectContext ctxt)
  	{
  		try
  		{
  			return def.apply(af.getValuesDefinitionLocator(), ctxt);
  		} catch (AnalysisException e)
  		{
  			return null;
  		}
  
  	}
docs: Return a list of external values that are read by the definition.
  
  @param def
  @param ctxt
  The context in which to evaluate the expressions.
  @return A list of values read.