multiple-value-bind

ToC

Allegro CL

ANSI Common Lisp

5 Data and Control Flow

5.3 Dictionary of Data and Control Flow

5.3.48 multiple-value-bind

Macro

Syntax:

multiple-value-bind ({var}*) values-form {declaration}* {form}*

{result}*

Arguments and Values:

var - a symbol naming a variable; not evaluated.

values-form - a form; evaluated.

declaration - a declare expression; not evaluated.

forms - an implicit progn.

results - the values returned by the forms.

Description:

Creates new variable bindings for the vars and executes a series of forms that use these bindings.

The variable bindings created are lexical unless special declarations are specified.

Values-form is evaluated, and each of the vars is bound to the respective value returned by that form. If there are more vars than values returned, extra values of nil are given to the remaining vars. If there are more values than vars, the excess values are discarded. The vars are bound to the values over the execution of the forms, which make up an implicit progn. The consequences are unspecified if a type declaration is specified for a var, but the value to which that var is bound is not consistent with the type declaration.

The scopes of the name binding and declarations do not include the values-form.

Examples:

 (multiple-value-bind (f r) 
     (floor 130 11)
   (list f r))  (11 9)

See Also:

let, multiple-value-call

Notes:

 (multiple-value-bind ({var}*) values-form {form}*)
 ==(multiple-value-call #'(lambda (&optional {var}* &rest #1=#:ignore)
                             (declare (ignore #1#))
                             {form}*)
                         values-form)

Allegro CL Implementation Details:

None.