Here's a nice debugging feature in Clojure. The inspect module lets you look at variables in a popup JFrame. The two examples below show how you quickly view data in a table or tree format. This is really handy to quickly view data from the REPL.
(clojure.inspector/inspect-tree '(1 (a b) 2 (c d) 3 (e f )))
Exploring our grocery numbers
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