values
values &rest object → {object}*
(setf (values &rest place) new-values)
object—an object.
place—a place.
new-value—an object.
7.9.1 4
7.9.1 5values returns the objects as multiple values2.
setf of values is used to store the multiple values2 new-values into the places. See Section 5.1.2.3 (VALUES Forms as Places).
(values) → ⟨no values⟩ (values 1) → 1 (values 1 2) → 1, 2 (values 1 2 3) → 1, 2, 3 (values (values 1 2 3) 4 5) → 1, 4, 5 (defun polar (x y) (values (sqrt (+ (* x x) (* y y))) (atan y x))) → POLAR (multiple-value-bind (r theta) (polar 3.0 4.0) (vector r theta)) → #(5.0 0.927295)
7.9.1 6Sometimes it is desirable to indicate explicitly that a function returns exactly one value. For example, the function
(defun foo (x y) (floor (+ x y) y)) → FOOreturns two values because
floor returns two values. It may be that the second value makes no sense, or that for efficiency reasons it is desired not to compute the second value. values is the standard idiom for indicating that only one value is to be returned:
(defun foo (x y) (values (floor (+ x y) y))) → FOOThis works because
values returns exactly one value for each of args; as for any function call, if any of args produces more than one value, all but the first are discarded.
None.
None.
values-list, multiple-value-bind, multiple-values-limit, Section 3.1 (Evaluation)
Since values is a function, not a macro or special form, it receives as arguments only the primary values of its argument forms.