7thSon@SLCS.SLB.COM (Chris Garrigues) (01/18/90)
I frequently use setf of backquoted forms to do destructuring: (setf `(,x ,y) (function-which-returns-a-two-element-list bar)) (I realize that this isn't actually part of legal common lisp, but it is useful.) The other day while thinking about this ability, I came up with an odd piece of code. Should this actually expand into something reasonable: (setf `(,(second x) ,(first x)) x) It looks to me like it should swap the first and second elements of the list x. It doesn't work on my LispM, however, because the two operations aren't done in "parallel". I lost sleep over this silliness last night. Chris