Does Calcite currently support converting a Linq4j expression to relational algebra? After a quick look at the code, it seems that it does not, so if not, do you think it is feasible? On one hand, the Linq4j expressions are very similar to the RelBuilder structure, (e.g., .groupBy(), .orderBy(), etc). On the other hand, the extensive use of functions (e.g., selectors) and in-memory data-types may be difficult to implement as a RelBuilder. The use case I have in mind is to have Linq4j as another top-level interface (that is interpretable to relational algebra) to Calcite in addition to SQL and Piglet.
Thanks, Walaa.
