Conduit Sink fork

t helfferich

4 Mar 2012 4 Mar '12

6:54 p.m.

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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Michael Snoyman

5 Mar 5 Mar

9:56 a.m.

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

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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

t helfferich

1:26 p.m.

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

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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

t helfferich

1:26 p.m.

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

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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

t helfferich

1:35 p.m.

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

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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

t helfferich

2:31 p.m.

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

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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

t helfferich

2:51 p.m.

Sorry for the repeat postings. My machine freaked out

...

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

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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

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Michael Snoyman
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