I present to you print-object, a generic function in Common Lisp. http://clhs.lisp.se/Body/f_pr_obj.htm http://clhs.lisp.se/Body/f_pr_obj.htm So say you have

I present to you print-object, a generic function in Common Lisp. http://clhs.lisp.se/Body/f_pr_obj.htm http://clhs.lisp.se/Body/f_pr_obj.htm So say you have a object type FOO, you can do this: (defmethod print-object ((obj FOO) stream) ...) Now, when you have a FOO on the repl, print-object will be called. Obviously it doesn't provide a drilldown approach and any number of nifty and useful functions.