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Showing posts from December, 2014

Using wye and tee with scalaz-stream

An updated version of this is available in a collection of user notes for scalaz-stream found at gitbook: scalaz-stream user notes at gitbook.

I needed to use scalaz-streams (sstreams) for some processing but was having problems understanding wye and tee. Here's a bunch of examples that illustrate what the functions do. You can read the specs in the tests, which are quite good. I needed a place to stash notes based on my work. Hence this article. Hopefully, it helps others learn faster. In the below examples, you need to remember that the Process is a moment-in-time capture of the state of the stream. As such, when you see a Wye or Tee object, it will be used once, but then the next process state will use another object instance. You sometimes starting wondering, at least I did, where does the object that remembers what you are doing live? Since each state carries with it enough information to generate the next state, give a suitable driver, you do not need a mutable, long lived …