Is there a way to extract all elements of a list in place

Question

Im looking for a way to extract all the elements of a list in common lisp. Like this

[194]> (break-out-of-list '(a b c d))
A
B
C
D

Edit: The usage example I gave was not thought out very well, however I'm still curious if it is possible to break out of a list like in the example above.

Answer 1

What you demonstrate seems to be the question how to get the elements of a list as multiple values:

CL-USER> (values 1 2 3)
1
2
3
CL-USER> (apply #'values '(1 2 3))
1
2
3

See also multiple-value-bind and nth-value in the hyperspec.

Answer 2

While (apply #'values '(1 2 3)) works there is also a function to this called values-list which is used like this:

(values-list '(1 2 3))

And it has the same result.

Answer 3

Sure, just use apply:

(defun wraptest (&rest arguments)
  (apply #'test arguments))

This technically doesn't "break out of list"; it simply uses a list's elements as arguments to a function call.

(Disclaimer: I'm a Schemer, not a Common Lisper, and there may be a more-idiomatic way to achieve the same result in CL.)