Iterator blocks in Clojure?
- by Checkers
I am using clojure.contrib.sql to fetch some records from an SQLite database.
(defn read-all-foo []
(with-connection *db*
(with-query-results res ["select * from foo"]
(into [] res))))
Now, I don't really want to realize the whole sequence before returning from the function (i.e. I want to keep it lazy), but if I return res directly or wrap it some kind of lazy wrapper (for example I want to make a certain map transformation on result sequence), SQL-related bindings will be reset and connection will be closed after I return, so realizing the sequence will throw an exception.
How can I enclose the whole function in a closure and return a kind of iterator block (like yield in C# or Python)?
Or is there another way to return a lazy sequence from this function?
