Shiro Kawai <xxxxxx@gmail.com> writes:

> On Sun, Jun 30, 2024 at 11:06 PM Maxime Devos <xxxxxx@telenet.be> wrote:
>
>  Optional return values work in Scheme too (e.g. consider call-with-values + case-lambda, ignore values you are not interested in). I
>
> The issue is that  if the API allows variable number of return values, you always need to handle it
> in the receiving side.

In all implementations I use, you can always ignore all values except
for the first by just using the return. Do you know ones that treat
multiple-values return differently?

(define deps (topological-sort ...)) ;; gets the first value

You have to explicitly request multiple values to see values two and
three.

(let-values (((res msg info) (topological-sort ...)))) ;; three values

That’s why I now changed the documentation to match the implementation:
always return three values.

Best wishes,
Arne
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