lambda-list—a destructuring lambda list.
expression—a form.
declaration—a declare expression; not evaluated.
forms—an implicit progn.
results—the values returned by the forms.
destructuring-bind
binds the variables specified in lambda-list
to the corresponding values in the tree structure resulting from the evaluation
of expression; then destructuring-bind
evaluates forms.
The lambda-list supports destructuring as described in Section 3.4.5 (Destructuring Lambda Lists).
(defun iota (n) (loop for i from 1 to n collect i)) ;helper
(destructuring-bind ((a &optional (b 'bee)) one two three)
`((alpha) ,@(iota 3))
(list a b three two one)) → (ALPHA BEE 3 2 1)
If the result of evaluating the expression does not match the
destructuring pattern, an error of type error
should be signaled.