What timing, I was in the middle of writing the same question to the list when I got this. I can only add that the problem is also present in 5.3.0.20, and that, if I take (for instance, the stream-map) definition in racket/stream and execute it again, stream-map begins working as expected again. Maybe a problem with generics?
On Wed, Aug 22, 2012 at 1:49 PM, Stephen Chang <stch...@ccs.neu.edu> wrote: > I've been playing with Racket streams and I am confused about what > exactly counts as a stream? For example, are lists streams? I think > the answer is yes but then are the stream- functions supposed to work > on regular lists? Some do but some don't. > > Welcome to DrRacket, version 5.3.0.16 [3m]. > Language: racket [custom]. > > (stream-map (λ (x) x) null) > . . plt/collects/racket/stream.rkt:113:0: stream-accessor: contract > violation > expected: stream? > given: '() > > (stream? null) > #t > > (stream-map (λ (x) x) (list 1 2)) > . . plt/collects/racket/stream.rkt:113:0: stream-accessor: contract > violation > expected: stream? > given: '(1 2) > > (stream? (list 1 2)) > #t > > (stream-first (list 1 2)) > 1 > > _________________________ > Racket Developers list: > http://lists.racket-lang.org/dev >
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