Exercise 4.74

Read Exercise 4.74 ~ Solution


a) simple-flatten‘s argument is a stream whose elements are either the empty stream or a singleton stream. We need to filter out elements that are the empty stream and then take the first element of each resulting stream.

(define (simple-flatten stream)
  (stream-map stream-car
              (stream-filter (λ (s)
                               (not (stream-null? s)))
                             stream)))

b) There is no difference in behaviour (as long as Alyssa’s assertions are correct.)

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3 thoughts on “Exercise 4.74

  1. Thanks for all your solutions. More than the solutions, I liked reading your experience while working through the more difficult problems. Reading your experience kept me motivated. Thank you.

  2. Thanks, I feel guilty that I stopped before finishing all the book exercises. I need to carve out some time to complete them.

  3. I also took a long break and restarted it this year. It took me quite a good time to come into context. Hoping to close it this time. Wish you will also get time to complete the remaining chapter.

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