@jetzajac: (project) can help: user=> (run* [q] (conde [(== q 1)] [(== q "foobar")]) (project [q] (== (type q) Long))) (1)
mind you, project is non-relational
yeah, that's kind of solution but I need a relational version of it if I want to write some interpreter.
Actually I found @dnolen version of it here https://github.com/webyrd/symbolo-numbero-tests-for-core-logic/blob/master/symbolo/src/symbolo/core.clj
Thus I'm not sure why it's not in the library then