Executing queries II
I continued working on the execution of SQL queries. I am trying to have a reasonably 'neat' implementation of the database part, which takes a little time. I expect to have it working tomorrow.
After that, I will start with the optimisation part, first with single expression optimisation (like in Kleisli). That means that a query will always be executed before the end of an expression: a value defined as the result of a query will be a list of records, not the query itself, even if executing it later might yield to further optimisations.
Later in this project, it might be interesting to look into lazy evaluation of queries.