• apply function &rest args+ → result*

• function - a function designator.
• args - a spreadable argument list designator.
• results - the values returned by function.

Applies the function to the args.

When the function receives its arguments via &rest, it is permissible (but not required) for the implementation to bind the rest parameter to an object that shares structure with the last argument to apply. Because a function can neither detect whether it was called via apply nor whether (if so) the last argument to apply was a constant, conforming programs must neither rely on the list structure of a rest list to be freshly consed, nor modify that list structure.

setf can be used with apply in certain circumstances; see section {\secref\SETFofAPPLY}.

(defparameter *f* '+) 

→

+



(apply *f* '(1 2)) 

→

3



(setf *f* #'-) 

→

# 



(apply *f* '(1 2)) 

→

-1 



(apply #'max 3 5 '(2 7 3)) 

→

7 



(apply 'cons '((+ 2 3) 4)) 

→

((+ 2 3) . 4) 



(apply #'+ '()) 

→

0



(defparameter *some-list* '(a b c)) 

→

*SOME-LIST*



(defun strange-test (&rest x)
  (eq x *some-list*)) 

→

STRANGE-TEST



(apply #'strange-test *some-list*) 

→

implementation-dependent



(defun bad-boy (&rest x) 
  (rplacd x 'y)) 

→

BAD-BOY



(bad-boy 'a 'b 'c)

?

The above has undefined consequences.



(apply #'bad-boy *some-list*)

?

The above has undefined consequences.



(defun foo (size &rest keys &key double &allow-other-keys)
  (let ((v (apply #'make-array size :allow-other-keys t keys)))
    (if double 
        (concatenate (type-of v) v v)
        v))) 

→

FOO



(foo 4 :initial-contents '(a b c d) :double t)

→

#(A B C D A B C D)

None.

None.

• Function FUNCALL
• Function FDEFINITION
• Special Operator FUNCTION
• {\secref\Evaluation}
• {\secref\SETFofAPPLY}

None.

\issue{FUNCTION-TYPE:X3J13-MARCH-88} \issue{REST-LIST-ALLOCATION:MAY-SHARE} \issue{REST-LIST-ALLOCATION:MAY-SHARE}