That's correct, you have to force before you append-map. As it turns out, we are working on exactly this issue at the moment, and your email was perfectly timed.
Thanks -- Matthias On Sep 3, 2011, at 12:14 PM, Daniil wrote: > Hello, I am trying to use the Lazy Racket for generating infinite lists. > Here's the code: > > #lang lazy > (require racket/list) > (define hamming > (list 1 > (append-map > (lambda (x) (list > (* 2 x) > (* 3 x) > (* 5 x))) hamming))) > > (define bla (take 5 (sort hamming <))) > > > However, when I evaluate (! bla) I get: > append: expected argument of type <proper list>; given #<promise> > > If I understand correctly this happens because I mix racket/list and > lazy? How can I avoid this? Should I use stream-cons? > > Thank you. > _________________________________________________ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/users _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
