I created a new repo in the datafusion-contrib GitHub org over the weekend with a starting point for supporting DataFusion as both a producer and consumer of Substrait plans.
https://github.com/datafusion-contrib/datafusion-substrait I am hopeful that we can eventually use Substrait in Ballista as a replacement for the current query plan protobuf format, meaning that the Ballista scheduler could potentially be used with engines other than DataFusion. I also think it could be helpful with in-memory language interoperability, such as passing query plans between Python and Rust. I plan on continuing to merge my own PRs here as I flesh out more of this, at least until there are other contributors. Thanks, Andy.
