Macro: P-POP

Documentation

Pop an item from the persistent list specified by PLACE.

Source

(defmacro p-pop (place &environment env)
  "Pop an item from the persistent list specified by PLACE."
  (multiple-value-bind (dummies vals new setter getter)
      (get-setf-expansion place env)
    `(let* (,@(mapcar #'list dummies vals) (,(car new) ,getter))
       (prog1 (p-car ,(car new))
         (setq ,(car new) (p-cdr ,(car new)))
         ,setter))))