multiple-value-setf

Purpose
Assign values to places.

Package   :gbbopen-tools

Module   :gbbopen-tools

Arguments and values

Returns
The primary value returned by form.

Description
The form is evaluated, and each place is assigned to the corresponding value returned by form. If nil is used one or more places, no assignment is made to the nil “place,” but the corresponding value is consumed (ignored). If there are more places than values returned, nil is assigned to the extra places. If there are more values than places, the extra values are discarded.

Examples

  > (setf *x* (cons 0 0))
  (0 . 0)
  > (multiple-value-setf ((car *x*) (cdr *x*)) (values 1 2 3))
  1
  > *x*
  (1 . 2)
  > (multiple-value-setf (nil nil (cdr *x*)) (values -1 -2 -3))
  -1
  > *x*
  (1 . -3)
  > (multiple-value-setf ((car *x*) (cdr *x*)) 100)
  100
  > *x*
  (100)
  > (multiple-value-setf ((car *x*) (cdr *x*)) nil)
  nil
  > *x*
  (nil)
  >

multiple-value-setf