Copied from https://github.com/GeorgeJahad/debug-repl which hasn't been maintained for 3 years.
Clojure breakpoints that open a sub-repl allowing inspection of current state within a given lexical scope
Original version written by George Jahad, with brilliant improvements by Alex Osborne and Konrad Hinsen
Jan 31, 2010
Copyright (c) George Jahad, Alex Osborne and Contributors. All rights reserved. The use and distribution terms for this software are covered by the Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php) which can be found in the file epl-v10.html at the root of this distribution. By using this software in any fashion, you are agreeing to be bound by the terms of this license. You must not remove this notice, or any other, from this software.