[racket-dev] racket/stream

At Thu, 17 Mar 2011 16:12:22 -0400, Matthias Felleisen wrote:
> 
> On Mar 17, 2011, at 4:10 PM, Matthew Flatt wrote:
> 
> > At Thu, 17 Mar 2011 15:53:51 -0400, Matthias Felleisen wrote:
> >> That's the heart of the question, its distillation to a one-liner. 
> >> 
> >> The real question how a list can __be__ a stream and how a LR stream can 
> >> __be__ a stream. 
> > 
> > It's in the same way that a list can be a sequence and a vector can be
> > a sequence.
> > 
> > The intent is that "stream" is an API that can be implemented for
> > multiple representations. The representations of streams created by
> > `stream-cons' and `cons' are different, but the `stream-empty?',
> > `stream-first', and `stream-rest' operations can support both of those
> > representations (and more).
> > 
> > This might be a generalization of "stream" as it is sometimes used (I'm
> > not sure), and we have already discarded an attempt to generalize
> > "generator". The difference is that generators support some operations
> > (such as arguments to the generator) that are not be supported by
> > stateful sequences in general. In contrast, functional sequences in
> > general support any operation that `stream-cons'-streams support. It's
> > just a question of how the stream is represented.
> 
> 
> I disagree only because of the lazy nature of stream __construction__, 
> the potential confusion for first-timers, and the potential confusion with
> some srfi or other. 

Can you provide an example that would create confusion?