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====== Macro DESTRUCTURING-BIND ====== ====Syntax==== * **destructuring-bind** //lambda-list expression declaration''*'' form''*''// //result''*''// ====Arguments and Values==== * //lambda-list// - a //[[CL:Glossary:destructuring lambda list]]//. * //expression// - a //[[CL:Glossary:form]]//. * //declaration// - a **[[CL:Special Operators:declare]]** //[[CL:Glossary:expression]]//; not evaluated. * //form//s - an //[[CL:Glossary:implicit progn]]//. * //result//s - the //[[CL:Glossary:value|values]]// returned by the //[[CL:Glossary:form|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 //form//s. The //lambda-list// supports destructuring as described in \secref\DestructuringLambdaLists. ====Examples==== <blockquote> ;;; TODO better examples for this, d-bind really deserves more love (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)) <r>(ALPHA BEE 3 2 1)</r> </blockquote> ====Affected By==== None. ====Exceptional Situations==== If the result of evaluating the //expression// does not match the destructuring pattern, an error of type **[[CL:Types:error]]** should be signaled. ====See Also==== * **[[CL:Special Operators:macrolet|Special Operator MACROLET]]** * **[[CL:Macros:defmacro|Macro DEFMACRO]]** ====Notes==== None. \issue{DECLS-AND-DOC} \issue{DESTRUCTURING-BIND:NEW-MACRO}