jorisvandenbossche commented on code in PR #14106:
URL: https://github.com/apache/arrow/pull/14106#discussion_r977663050


##########
cpp/src/arrow/compute/kernels/scalar_cast_extension.cc:
##########
@@ -42,14 +42,17 @@ Status CastToExtension(KernelContext* ctx, const ExecSpan& 
batch, ExecResult* ou
 
 std::shared_ptr<CastFunction> GetCastToExtension(std::string name) {
   auto func = std::make_shared<CastFunction>(std::move(name), Type::EXTENSION);
-  for (auto types : {IntTypes(), FloatingPointTypes(), StringTypes(), 
BinaryTypes()}) {
+  for (auto types : {PrimitiveTypes(), IntervalTypes(), TemporalTypes()}) {
     for (auto in_ty : types) {
       DCHECK_OK(
           func->AddKernel(in_ty->id(), {in_ty}, kOutputTargetType, 
CastToExtension));
     }
   }
-  DCHECK_OK(func->AddKernel(Type::DICTIONARY, {InputType(Type::DICTIONARY)},
-                            kOutputTargetType, CastToExtension));
+  for (auto in_ty : {Type::DICTIONARY, Type::LIST, Type::LARGE_LIST,
+                     Type::FIXED_SIZE_LIST, Type::EXTENSION}) {

Review Comment:
   I am not sure we should special case extension->extension casts. For a given 
extension type, there might be casts based on the storage type that _also_ 
don't make much sense, so it is hard for us to know in general what cast makes 
sense or not. 
   
   For a specific use case, in the geometry types, we might have an extension 
type backed by a nested type with float or double coordinate values. Being able 
to cast from Extension(List<float>) <-> Extension(List<double>) would make 
sense in our case.



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]

Reply via email to