Re: [Haskell-cafe] Conduit Sink fork

Thanks. That makes sense.Grant

From: michael@snoyman.com Date: Mon, 5 Mar 2012 16:56:11 +0200 Subject: Re: [Haskell-cafe] Conduit Sink fork To: thelff@hotmail.com CC: haskell-cafe@haskell.org

On Mon, Mar 5, 2012 at 1:54 AM, t helfferich wrote:

...

Hi! So, it turns out I have a need for a sink that forks input into two other sinks using the Conduit package. Here is what I came up with: https://gist.github.com/1975383

Is this the right way to write it? Also, what left over value(s) should I return in the Done constructor?

I appreciate any help you can give me.

Thanks so much, Grant

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It looks like the right approach to me. What to do with the leftover values is a really good question, and I don't think there's really an obvious answer. I can think of a few approaches:

* What you've done: never return leftover values. * Always return the ll (or rr). * Return whichever leftover value is Just, or if both are Just, arbitrarily choosing one of them

Similarly, you could take different approaches to what to do when processing terminates early:

* What you've done: continue pushing data until both Sinks return Done * Terminate whenever the left (or right) Sink returns Done * Terminate when *either* returns Done

Again, there's no right answer here, they all seem like valid approaches.

Michael