destructuring-bind [Macro]

destructuring-bind lambda-list expression {declaration}{* {form}{*}}
=> {result}{*}

Arguments and Values::

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.

Description::

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 Destructuring Lambda Lists.

Examples::

 (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)

Exceptional Situations::

If the result of evaluating the expression does not match the destructuring pattern, an error of type error should be signaled.

See Also::

macrolet, section defmacro [Macro]

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