On Thu, 26 May 2011 11:34:48 -0400, Eli Barzilay <eli@barzilay.org> wrote:

> This is a question for WG1 (collectively):
>
> According to R5RS, is this code:
>
>   (call-with-values
>     (lambda ()
>       (call-with-current-continuation (lambda (k) (k 1 2 3))))
>     (lambda (x y z) 'ok))
>
> allowed to throw an error, or to return anything other than 'ok ?

I strongly believe that the above code must return the symbol 'ok'. The
wording of the R5RS is not, IMO, ambiguous here. The continuation k
receives its values and is required to then pass these to the three
argument lambda [fuzzy wording, I know], and since the correct number of
arguments are indeed passed, I fail to find any room for unspecified
behavior. I believe the only unspecified behavior that R5RS deals with in
this case is whether a continuation expecting X number of values receives
Y number of values, where X≠Y.

You ask for the collective WG1 voice on this, and unfortunately, I do not
think that we have a mechanism for this. However, we can file a ticket
concerning this issue and decide on it. Since even Chibi returns the
symbol ok for the above now (after Alex's fix), I don't think the above
code is particularly contentious anymore.

If someone disagrees, please, let's hear it.

	Aaron W. Hsu

--
Programming is just another word for the lost art of thinking.

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