racket/pkgs/racket-doc/scribblings/reference/values.scrbl
Matthew Flatt 4354ce45d8 use `scribble/examples' for the Reference
Port `examples`, `interactions`, etc., to use the new `examples`
form of `scribble/examples`. The main intended effect is to ensure
that errors are produced by examples only as specifically
indicated.
2015-12-11 12:29:41 -07:00

36 lines
1.1 KiB
Racket

#lang scribble/doc
@(require "mz.rkt")
@title[#:tag "values"]{Multiple Values}
See @secref["values-model"] for general information about multiple
result values. In addition to @racket[call-with-values] (described in
this section), the @racket[let-values], @racket[let*-values],
@racket[letrec-values], and @racket[define-values] forms (among
others) create continuations that receive multiple values.
@defproc[(values [v any/c] ...) any]{
Returns the given @racket[v]s. That is, @racket[values] returns its
provided arguments.
@examples[
(values 1)
(values 1 2 3)
(values)
]}
@defproc[(call-with-values [generator (-> any)] [receiver procedure?]) any]{
Calls @racket[generator], and passes the values that
@racket[generator] produces as arguments to @racket[receiver]. Thus,
@racket[call-with-values] creates a continuation that accepts any
number of values that @racket[receiver] can accept. The
@racket[receiver] procedure is called in tail position with respect to
the @racket[call-with-values] call.
@examples[
(call-with-values (lambda () (values 1 2)) +)
(eval:error (call-with-values (lambda () 1) (lambda (x y) (+ x y))))
]}