Re: values->list elements

[szgyg <szgyg@freemail.hu>]

Jon Wilson wrote:
> Is there any sensible way to implement the following semantics:
> 
> (+ (values 1 2))
> ==>
> 3
 >
> Or perhaps with a macro of some sort (but preferably as above)...
> 
> (+ (values->list-elements (values 1 2)))
> ==>
> 3

! untested code !

(define-macro (values->list vs)
    `(call-with-values (lambda () ,vs) list))

(apply + (values->list (values 1 2 3)))

or

(define-macro (make-cockeyed-function f)
    `(lambda (vs) (apply ,f (values->list vs))))

((make-cockeyed-function +) (values 1 2 3))

> The intermediate step (after the macro expansion I guess) would look like
> 
> (+ 1 2)

No, this is impossible without redefining +. A macro produces 1 sexp, 
not more.

> It seems like this would make multiple values much much more useful.

szgyg

ps: GNU Free Software Directory list guile-1.6.7 as recent


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