returnString commented on pull request #9703: URL: https://github.com/apache/arrow/pull/9703#issuecomment-798918286
> I couldn't figure out how to allow the Dataframe API (which is a Trait) to take an impl Iterator<Item=Expr> Yeah, it's a pain but `impl trait` (in both return and argument position) isn't supported in traits right now. Afaik there were some historical discussions about opening up the system to support it but I can't find anything recent. Related: is there a reason that `DataFrame` is a trait with a single impl? I'm wondering if it could be a concrete struct with the actual execution logic handling more exotic setups (custom `TableProvider` impls etc), which would free it from all the trait-imposed restrictions. Are we expecting to support multiple DF implementations? ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected]
