Setting up sbt environment to hack on multiple libraries at once

Question

Is there an equivalent to Leiningen's "checkouts" feature in sbt?

Here is what I want to accomplish:

I have two projects, an application Foo and library "Bar". I want to publish each of these projects independently. Foo depends on Bar, and the sbt project will direct sbt to download the jar for "Bar" from a repository whenever a third-party tries to build "Foo" (which is typical behavior).

Now, say I want to hack on both Foo and Bar at the same time. For example, while working on Foo, I want to directly edit and debug some of the source for Bar so the edits affect Foo (and then later rebuild Bar when it is convenient).

How can I instruct sbt to satisfy its dependency on Bar from its source code on my machine (rather than my local repository) during this hack session?

(P.S. I asked a similar question for Clojure/Leiningen. Leiningen has the "checkouts" feature which accomplishes this. I am wondering if there is something similar in sbt...)