The in-X forms are sequences, and must be used with the sequence API, ie for/X.
map only works with lists, so you could use build-list or range:
(map
foo
lst-A
lst-B
(range 2))
On Thu, Mar 2, 2017 at 9:55 AM, David Storrs <david.sto...@gmail.com> wrote:
> I'd like to be able to do something like this:
>
> (struct foo (a b c))
> (define lst-A '(a b))
> (define lst-B '(d e))
> (map
> foo
> lst-A
> lst-B
> (in-naturals))
>
> I'd expected this to produce: (foo 'a 'd 0) (foo 'b 'e 1), but instead it
> throws an exception "expected list, given stream". I could do it with a
> for/list but that's much more verbose. What would be the idiomatic way of
> doing this?
>
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