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Today's Topics:
1. Re: Using findIndex and then splitAt in Data.List
(Francesco Ariis)
2. Bounded STM Queues with load shedding (Alex Hammel)
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Message: 1
Date: Fri, 27 Feb 2015 23:18:47 +0100
From: Francesco Ariis <[email protected]>
To: [email protected]
Subject: Re: [Haskell-beginners] Using findIndex and then splitAt in
Data.List
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
On Fri, Feb 27, 2015 at 04:51:46PM -0500, David McBride wrote:
> Another way you can deal with this is using the maybe function.
> If you are absolutely positive that it can never fail, it doesn't
> hurt to choose a default index of 0.
>
> let gradeItemIndex = ...
> let twoListsTuple = splitAt (maybe 0 id gradeItemIndex)
And if you don't trust your gut feelings, instead of `maybe 0...` place
maybe (error "tlt") id gradeItemIndex
as some kind of crude assertion.
------------------------------
Message: 2
Date: Fri, 27 Feb 2015 14:32:07 -0800
From: Alex Hammel <[email protected]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Subject: [Haskell-beginners] Bounded STM Queues with load shedding
Message-ID:
<ca+_xfepyvsbyyzc24tuocmg2t+fpwtaas9cu+btlq3+kfae...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Hi list,
It would be handy for me to have a bounded STM Queue along the lines of
TBQueue
<https://hackage.haskell.org/package/stm-2.4/docs/Control-Concurrent-STM-TBQueue.html>
with the difference that when the queue is full, a call to writeTBQueue is
a non-blocking no-op.
This is in the context of an asynchronous logging system. If the load
(somehow) gets heavy enough that the log message queue is taking up a lot
of memory, It's better to lose a few log messages than to have processes
block until the logger catches up.
Are there any off-the-shelf solutions?
Cheers,
Allex
<https://hackage.haskell.org/package/stm-2.4/docs/Control-Concurrent-STM-TBQueue.html>
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