On 30.04.15 21:36, Karsten Poeck wrote: > On 30.04.15 20:08, Ron Garret wrote: >> (flet ((+ () t)) t) > Not sure whether you consider this a solution, but did you try shadowing +? I am aware that you wrote "The Complete Idiot’s Guide to Common Lisp Packages", just wonder why you didn't use packages here. Karsten