Welcome to issue 252 of the HWN, an issue covering crowd-sourced bits
of information about Haskell from around the web. This issue covers the
week of November 18 to 24, 2012.
Quotes of the Week
* rwbarton: edwardk now has Lens under Control
* atriq: My son looks a bit like me, he can put a
On 29 November 2012 01:08, Roman Beslik wrote:
> Hi. There is more verbose page http://www.haskell.org/haskellwiki/IDEs . I
> registered on http://www.haskell.org/haskellwiki/ , but have not found the
> "Delete Page" command, wiki software help pages, or feedback channel, so I'm
> writing here.
I
Dan Doel wrote:
> On Tue, Oct 16, 2012 at 10:37 AM, AUGER Cédric wrote:
>> join IS the most important from the categorical point of view.
>> In a way it is natural to define 'bind' from 'join', but in Haskell, it
>> is not always possible (see the Monad/Functor problem).
>>
>> As I said, from the
Tony Morris wrote:
> As a side note, I think a direct superclass of Functor for Monad is not
> a good idea, just sayin'
>
> class Functor f where
> fmap :: (a -> b) -> f a -> f b
>
> class Functor f => Apply f where
> (<*>) :: f (a -> b) -> f a -> f b
>
> class Apply f => Bind f where
> (=
Hi Everyone
just wanted to drop by to say how much I like the new lambda case extension.
I use it all the time and I just *love* how it relieves me from conjuring up
dummy variables, which makes teh code not only esier to write but also to
read.
A big, huge thank you to the ghc developers. Thi
No - the difference is 6.5ms each way
On 28 Nov 2012, at 14:44, Alexander Kjeldaas
wrote:
>
> Jeff, this is somewhat off topic, but interesting. Are "telehouse" and AWS
> physically close? Was this latency increase not expected due to geography?
>
> Alexander
>
> On 28 November 2012 06:
If you have rdrand, there is no need to build your own PRNG on top of
rdrand. RdRand already incorporates one so that it can produce random
numbers as fast as they can be requested, and this number is continuously
re-seeded with the on-chip entropy source.
It would be nice to have a little mor
On Wed, Nov 28, 2012 at 8:36 PM, Jeff Shaw wrote:
> On 11/27/2012 4:59 PM, Nicolas Wu wrote:
> I pulled the latest version of HDBC-odbc, and it appears to be working MUCH
> better than before. I now have 0% timeouts from httperf with 50
> connections/second and timeout set to 0.1 seconds. It's loo
On 11/28/2012 09:31 PM, Leon Smith wrote:
Quite possibly, entropy does seem to be a pretty lightweight
dependency...
Though doesn't recent kernels use rdrand to seed /dev/urandom if it's
available? So /dev/urandom is the most portable source of random
numbers on unix systems, though rdran
Quite possibly, entropy does seem to be a pretty lightweight dependency...
Though doesn't recent kernels use rdrand to seed /dev/urandom if it's
available? So /dev/urandom is the most portable source of random numbers
on unix systems, though rdrand does have the advantage of avoiding system
ca
On 11/27/2012 4:59 PM, Nicolas Wu wrote:
Hi, I'm the maintainer of HDBC. I haven't yet released this code since
it hasn't yet been fully tested. However, if you're happy with it,
I'll push the version with proper ffi bindings up to Hackage. Nick
Nick,
I pulled the latest version of HDBC-odbc,
On Wed, Nov 28, 2012 at 3:24 PM, Roman Beslik wrote:
> A humble link "What links here" to the right will help you find those pages.
Only for wikipages, nowhere else on the Internet.
--
gwern
http://www.gwern.net
___
Haskell-Cafe mailing list
Haskell-
A humble link "What links here" to the right will help you find those pages.
On 28.11.12 21:53, Brent Yorgey wrote:
is probably not a good idea anyway -- what if there are other pages
that link to it?
On Wed, Nov 28, 2012 at 07:08:16PM +0200, Roman Beslik wrote:
Hi. There is more verbose pag
On 11/28/2012 08:38 PM, Leon Smith wrote:
> I have some code that reads (infrequently) small amounts of data from
> /dev/urandom, and because this is pretty infrequent, I simply open the
> handle and close it every time I need some random bytes.
>
> The problem is that I recently discovered that
Yes, monomorphism. "do" binding requires your fold'' to be of some monomorphic
type, but runST requires some polymorphism.
If you want, you can use special type like that:
data FoldSTVoid = FoldSTVoid {runFold :: forall a. (Int -> ST a ()) -> ST a ()}
fold :: Monad m => (Int -> m ()) -> m ()
fo
On Wed, Nov 28, 2012 at 07:08:16PM +0200, Roman Beslik wrote:
> Hi. There is more verbose page
> http://www.haskell.org/haskellwiki/IDEs . I registered on
> http://www.haskell.org/haskellwiki/ , but have not found the "Delete
> Page" command, wiki software help pages, or feedback channel, so I'm
>
As an alternative, If there existed a Haskell package to give you fast
cryptographically secure random numbers or use the new Intel RDRAND
instruction (when available) would that interest you?
Also, what you are doing is identical to the "entropy" package on
hackage, which probably suffers from th
I have some code that reads (infrequently) small amounts of data from
/dev/urandom, and because this is pretty infrequent, I simply open the
handle and close it every time I need some random bytes.
The problem is that I recently discovered that, thanks to buffering within
GHC, I was actually
I think OpenAL is now unmaintained. You could try to find AndrewMiller
who updated the last version, otherwise you might have to patch it
yourself or ask a developer of a dependent package if they would
consider pushing another "unmaintained" release to Hackage.
___
On 11/28/2012 07:01 PM, Stephen Tetley wrote:
Hi Gary
Which version of GHC are you using?
My suspicion is that ALCdevice might be a newtype falling foul of
recent changes to GHC...
v7.4.1: "GHC now requires, as per the standard, that if a newtype is
used in an FFI declaration, then the constr
Hi Gary
Which version of GHC are you using?
My suspicion is that ALCdevice might be a newtype falling foul of
recent changes to GHC...
v7.4.1: "GHC now requires, as per the standard, that if a newtype is
used in an FFI declaration, then the constructor for that type must be
in scope. For now you
Dear all,
I came up with an idea to greatly simplify some kinds of array
computations. It should work well with many kinds of arrays. Is this new?
https://gist.github.com/4162375
These few days, I've been trying to rewrite a hydrodynamic simulation code
that used Data.Vector (~250 lines), to R
Hi Cafe,
I try to implement some sort of monadic fold, where traversing is
polymorphic over monad type.
The problem is that the code below does not compile. It works with any
monad except for ST.
I suspect that monomorphism is at work here, but it is unclear for me how
to change the code to make i
Hi. There is more verbose page http://www.haskell.org/haskellwiki/IDEs .
I registered on http://www.haskell.org/haskellwiki/ , but have not found
the "Delete Page" command, wiki software help pages, or feedback
channel, so I'm writing here.
___
Haske
By tracing how unittyped produced the 'True-s and 'False-s in the error
messages, and by Oleg's lecture,
> 1 meter + 5 second
:17:9:
Couldn't match type 'False with 'True
When using functional dependencies to combine
UnitTyped.And 'False 'False 'False,
arising from the depen
Jeff, this is somewhat off topic, but interesting. Are "telehouse" and AWS
physically close? Was this latency increase not expected due to geography?
Alexander
On 28 November 2012 06:21, Neil Davies wrote:
> Jeff
>
> Are you certain that all the delay can be laid at the GHC runtime?
>
> How mu
Dear Cafe,
after installing the Sox library
(cabal install sox)
I wanted to let run a minimal example from
http://hackage.haskell.org/packages/archive/sox/0.2.2.2/doc/html/Sound-Sox-Play.html
module Main where
import Sound.Sox.Play
import Sound.Sox.Signal.List
--import Sound.Sox.Option.Format
Thank you very much! That solved it ;)I had to put explicit type signature in
front of advance in order to compile
From: cgae...@uwaterloo.ca
Date: Wed, 28 Nov 2012 08:01:38 -0500
Subject: Re: [Haskell-cafe] How to incrementally update list
To: edwards.b...@gmail.com
CC: bm...@hotmail.com; haskel
Dear Haskell Cafe,
I tried installing the haskell openal library via
cabal install openal
I get the following error:
...
[ 7 of 30] Compiling Sound.OpenAL.ALC.QueryUtils (
Sound/OpenAL/ALC/QueryUtils.hs, dist/build/Sound/OpenAL/ALC/QueryUtils.o )
Sound/OpenAL/ALC/QueryUtils.hs:66:1:
Unac
> I want to incrementally update list lot of times, but don't know how to
do this.
Are you using the right data structure for the job? Maybe you want an array
instead?
-- Kim-Ee
On Wed, Nov 28, 2012 at 6:43 PM, Branimir Maksimovic wrote:
> Problem is following short program:
> list = [1,2,3,4
Here's a version that works:
*import Control.DeepSeq*
list = [1,2,3,4,5]
advance l = *force $* map (\x -> x+1) l
run 0 s = s
run n s = run (n-1) $ advance s
main = do
let s = run 5000 list
putStrLn $ show s
The problem is that you build of a huge chain of updates to the l
TCO + strictnesses annotations should take care of your problem.
On 28 Nov 2012 11:44, "Branimir Maksimovic" wrote:
> Problem is following short program:
> list = [1,2,3,4,5]
>
> advance l = map (\x -> x+1) l
>
> run 0 s = s
> run n s = run (n-1) $ advance s
>
> main = do
> let s = run
Problem is following short program:list = [1,2,3,4,5]
advance l = map (\x -> x+1) l
run 0 s = srun n s = run (n-1) $ advance s
main = dolet s = run 5000 listputStrLn $ show s
I want to incrementally update list lot of times, but don't knowhow to do
this.Since Haskell does not
Jeff
Are you certain that all the delay can be laid at the GHC runtime?
How much of the end-to-end delay budget is being allocated to you? I recently
moved a static website from a 10-year old server in telehouse into AWS in
Ireland and watched the access time (HTTP GET to check time on top ind
On Wed, 2012-11-28 at 09:17 +0200, Michael Snoyman wrote:
>
>
>
> On Tue, Nov 27, 2012 at 7:25 PM, Nicolas Trangez
> wrote:
> Michael,
>
> On Tue, 2012-11-27 at 17:14 +0200, Michael Snoyman wrote:
> > I think the stm-conduit package[1] may be helpful for this
>
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