[racket] Problem Stream with alternating values

From: Patrick Sweetman (sweetman.p.c at xtra.co.nz)
Date: Tue May 21 20:50:33 EDT 2013

You are correct in this, Shannon, and you have nicely explained all of
the otherwise confusing clues about thunks.

 I shall revisit these problems from the point of view of view of the

The section of Dan Grossman's video lectures that deal with Racket are
an excellent introduction to the language.

-- Patrick

On 22/05/2013 08:23, Shannon Severance wrote:
> Patrick,
>> I saw that. The requirement for a stream of alternating values was
>> clearly stated, but then it confusingly talked about the internal
>> structure of a stream.  Surely if the stream is constructed by
>> stream primitives then it will all be thunked.  Or do you read the
>> problem as requiring that the stream itself be separately thunked?
> Is this from the archive on Coursera "Programming Languages" taught by
> Dan Grossman? If Racket's built in streams were mentioned at all it
> was to say something like, Racket has built in support for streams,
> but for the purpose of this class we are going to implement our own
> streams.
> The videos "Using Streams" and "Defining Streams" in section 5 covers
> how to use and implement streams. There is a summary in the section 5
> reading notes. Racket stream primitives make no appearance.
> -- Shannon

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