"James M. Lawrence" <llmjj...@gmail.com> writes:
> Using two loops seems awkward to me. How about one?
>
> (defun delete-from-plist (plist &rest keys)
> (loop with head = plist
> with tail = nil
> for (key . rest) on plist by #'cddr
> do (assert rest () "Expected a proper plist, got ~S" plist)
> (if (member key keys :test #'eq)
> (let ((next (cdr rest)))
> (if tail
> (setf (cdr tail) next)
> (setf head next)))
> (setf tail rest))
> finally (return head)))
I mention this for completeness and novelty, not for suitability:
(defun sans (plist &rest keys)
(let ((sans ()))
(loop
(let ((tail (nth-value 2 (get-properties plist keys))))
;; this is how it ends
(unless tail
(return (nreconc sans plist)))
;; copy all the unmatched keys
(loop until (eq plist tail) do
(push (pop plist) sans)
(push (pop plist) sans))
;; skip the matched key
(setq plist (cddr plist))))))
I don't think I've seen GET-PROPERTIES and NRECONC outside this
function.
I got it from here:
http://xach.com/naggum/articles/3247672165664225%40naggum.no.html
Zach
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