Esoteric: I use print debugging on a Lisp Machine using a presentation based Read Eval Print Loop (REPL), similar things would work in some other Common Lisp en

Esoteric: I use print debugging on a Lisp Machine using a presentation based Read Eval Print Loop (REPL), similar things would work in some other Common Lisp environments. Presentation based means that the REPL remembers all output and the objects associated with that output. (defmethod move ((a-ship object) (a-place port)) ; do something ) (defmethod move :around (what where) (print `(start moving object ,what to ,where)) (call-next-method)) Above prints the list to the REPL. The REPL prints the list as data, with the objects WHAT and WHERE included. It remembers that a specific printed output is caused by some object. Later these objects can be inspected or one can call functions on them... This combines print debug statements with introspection in a read-eval-print-loop (REPL). Writing the output as :before/:around/:after methods or as advise statements, makes it later easier to remove all print output code, without changing the rest of the code. -> methods and advises can be removed from the code at runtime.