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call-with-values
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10.1 Multiple Values

See Multiple Return Values for general information about multiple result values. In addition to call-with-values (described in this section), the let-values, let*-values, letrec-values, and define-values forms (among others) create continuations that receive multiple values.

procedure

(values v ...) → any

  v : any/c
Returns the given vs. That is, values returns its provided arguments.

Examples:

> (values 1)

1

> (values 1 2 3)

1

2

3

> (values)

procedure

(call-with-values generator receiver) → any

  generator : (-> any)
  receiver : procedure?
Calls generator, and passes the values that generator produces as arguments to receiver. Thus, call-with-values creates a continuation that accepts any number of values that receiver can accept. The receiver procedure is called in tail position with respect to the call-with-values call.

Examples:

> (call-with-values (lambda () (values 1 2)) +)

3

> (call-with-values (lambda () 1) (lambda (x y) (+ x y)))

#<procedure>: arity mismatch;

 the expected number of arguments does not match the given

number

  expected: 2

  given: 1

  arguments...:

   1

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