Because SQLite runs inside the Ruby process, SQL queries can call Ruby code directly. Users can register scalar functions (e.g. a silly `sort_letters` that alphabetizes characters in a string) and aggregate functions (written similarly to Ruby reduce) with declared arity. Application code, ActiveSupport, and any loaded gems are all in scope. Wrona presents this as a powerful extension point when no native SQLite extension exists — though his team has not yet used it in production.