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(library (my-streams)
(export stream-ordered-diff stream-merge)
(import (rnrs base) (srfi srfi-41))
(define-stream (stream-ordered-diff xstrm ystrm)
(stream-match xstrm (() '()) ((x . xs)
(stream-match ystrm (() xstrm) ((y . ys)
(cond ((< x y) (stream-cons x (stream-ordered-diff xs ystrm)))
((> x y) (stream-ordered-diff xstrm ys))
(else (stream-ordered-diff xs ys))))))))
(define-stream (stream-merge xstrm ystrm)
(stream-match xstrm (() ystrm) ((x . xs)
(stream-match ystrm (() xstrm) ((y . ys)
(cond ((< x y) (stream-cons x (stream-merge xs ystrm)))
((> x y) (stream-cons y (stream-merge xstrm ys)))
(else (stream-cons x (stream-merge xs ys)))))))))
)
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