Finish implementation of type casting.

src/ngraph/type.hpp

@@ -39,8 +39,12 @@ namespace ngraph
         using ptr = std::shared_ptr<ValueType>;
 
         virtual ~ValueType() {}
-        virtual std::shared_ptr<TensorViewType> as_tensor_view_type() { return nullptr; }
-        virtual std::shared_ptr<TupleType>      as_tuple_type() { return nullptr; }
+        
+        /**
+         ** Unmanaged cast to a supertype. dynamic_cast cannot be used
+         ** directly on a shared_ptr.
+         **/ 
+        template<typename T> T as() { return dynamic_cast<T>(this); }
     };
 
     /**

src/ops/op.cpp

@@ -55,7 +55,7 @@ void BroadcastCall::propagate_types()
     {
         throw ngraph_error("Argument to broadcast is missing type.");
     }
-    auto arg_tensor_view_type = arg_type->as_tensor_view_type();
+    auto arg_tensor_view_type = arg_type->as<TensorViewType*>();
     if (nullptr == arg_tensor_view_type)
     {
         throw ngraph_error("Argument to broadcast is not a tensor view");
@@ -103,8 +103,8 @@ Node::ptr ngraph::op::dot(const Node::ptr& arg0, const Node::ptr& arg1)
 
 void DotCall::propagate_types()
 {
-    auto arg0_tensor_type = m_arguments.at(0)->type()->as_tensor_view_type();
-    auto arg1_tensor_type = m_arguments.at(1)->type()->as_tensor_view_type();
+    auto arg0_tensor_type = m_arguments.at(0)->type()->as<TensorViewType*>();
+    auto arg1_tensor_type = m_arguments.at(1)->type()->as<TensorViewType*>();
     if (nullptr == arg0_tensor_type || nullptr == arg1_tensor_type)
     {
         throw ngraph_error("Arguments to dot must be tensor views");