>> All system calls issued from the network package use non-blocking.
>> You don't have to worry about blocking at all.
>
> Almost. Especially when interfacing with C code you should include the
> "-threaded" option to GHC to link against the multi-threaded run-time
> system. Otherwise your Hask
Kazu Yamamoto (山本和彦) wrote:
> > One last question. When writing C code, using epoll apis explicitly
> > can impose some blocking. Is the same to be said for GHC.Event?
>
> I don't understand your question.
>
> All system calls issued from the network package use non-blocking.
> You don't have to
Pointers.
Seriously.
In Haskell one could use STRef rather than the cumbersome Foreign.Ptr,
though STRef too can be kludgy.
I know not whether safe, pure, immutable pointers would be possible in
Haskell, but in my experience STRef can work well enough.
Cheers,
Strake
__
Welcome to issue 244 of the HWN, an issue covering crowd-sourced bits
of information about Haskell from around the web. This issue covers the
week of September 9 to September 15, 2012.
Inbox
As you might have heard, GHC 7.6.1 is out for all platforms. I would
say "get it while it is still hot",
On Wed, Sep 19, 2012 at 8:36 PM, wren ng thornton wrote:
>> P.S. It is actually possible to write zip function using Boehm-Berarducci
>> encoding:
>> http://okmij.org/ftp/ftp/Algorithms.html#zip-folds
>
>
> Of course it is; I just never got around to doing it :)
If you do, you might want
Hi,
> Is it true that writing a simple server using forkIO now integrates
> native event loops implicitly?
Yes.
IO manager handles event driven stuff. Thanks to this, we can enjoy
(light) thread programming using forkIO.
> One last question. When writing C code, using epoll apis explicitly
> c
On 9/18/12 4:27 AM, o...@okmij.org wrote:
There has been a recent discussion of ``Church encoding'' of lists and
the comparison with Scott encoding.
I'd like to point out that what is often called Church encoding is
actually Boehm-Berarducci encoding. That is, often seen
newtype ChurchList a =
On 9/18/12 8:32 AM, Jan Stolarek wrote:
Hi list,
I have yet another question about folds. Reading here and there I encountered
statements that
foldr is more important than foldl, e.g. in this post on the list:
http://www.haskell.org/pipermail/haskell-cafe/2012-May/101338.html
I want to know are
On 12-09-18 07:37 PM, Richard O'Keefe wrote:
On 19/09/2012, at 1:43 AM, Stefan Monnier wrote:
The problem with that is that some people DO end some headings with
a full stop; for them your special syntax is not natural.
Markdown/ReST is already using the "no syntax" idea (e.g. compared to
pr
Hi all,
I am pleased to announce the first release of One-Liner, a package for writing
short and concise generic instances of type classes. It works a bit like
Scrap-Your-Boilerplate, but it uses the new constraint kinds instead of the
Typeable class.
On hackage: http://hackage.haskell.org/pac
On Wed, Sep 19, 2012 at 8:00 PM, wrote:
> So how do I force IO actions whose results are discarded (including IO ()) to
> be strict?
In your particular case it looks like you want
Data.IORef.modifyIORef'. If your version of GHC doesn't include it you
can write it like so:
-- |Strict version of
Hi!
On 19/09/12 19:00, sdiy...@sjtu.edu.cn wrote:
> So how do I force IO actions whose results are discarded (including IO ()) to
> be strict?
() <- foo :: IO () -- should work as it pattern matches, can wrap it in
a prettier combinator
!_ <- foo :: IO a -- could work with -XBangPatterns
I've n
So how do I force IO actions whose results are discarded (including IO ()) to
be strict?
main = do
s<-newIORef (1::Int)
let
f :: Int -> Int -> IO Int
f 0 !acc = return acc -- note strict accumulator
f n !acc = do
On Wed, Sep 19, 2012 at 7:24 PM, wrote:
> main = do
> let
> f 0 acc = return acc
> f n acc = do
> v <- return 1
> f (n-1) (v+acc)
> f 100 100 >>= print
Try this
main = do
let
f :
A follow-up question.
I still haven't got the monadic version working, and the real use case involves
IO actions.
I looked at http://www.haskell.org/haskellwiki/Recursion_in_a_monad and adapted
the 'tail-recursive' snippet on the page into
main = do
let
f 0 acc = return
Now I have discovered the right version...
main = print (f 1 0::Int) where
f i s = (if i<=2 then (f (i+1) (s + g 1 0)) else s) where
g j s = (if j<=2 then (g (j+1) (s + i*j)) else s)
- 原始邮件 -
发件人: sdiy...@sjtu.edu.cn
收件人: haskell-cafe@haskell.org
发送时间: 星期三,
Hi cafe
looking at
http://www.haskell.org/haskellwiki/Simple_Servers
The last two solutions compared are forkIO vs. explicit event support
(based on what was System.Event).
Further reading appears to indicate that event support has been
integrated into the runtime.
Is it true that writing a si
I need to implement fast two-level loops, and I am learning using seq to make
calls tail-recursive.
I write programs to compute
main = print $ sum [i*j|i::Int<-[1..2],j::Int<-[1..2]]
This program (compiled with -O2) runs twenty times slower than the unoptimized
(otherwise the loop gets
On Wed, Sep 19, 2012 at 7:06 AM, Jason Dusek wrote:
> What I attempted was building a binary with only some C libraries
> statically linked, with this command line:
>
> # Build https://github.com/erudify/sssp on Ubunut 12.04
> ghc -outputdir ./tmp -v --make -O2 sssp.hs -o sssp.ubuntu \
>
2012/9/19 Christian Maeder :
> I usually just copy those .a files (that should be linked statically) into
> `ghc --print-libdir`.
Wow, it worked! But this isn't the sort of change I'd to a user's
system that I'd like to encode in a Makefile...
--
Jason Dusek
pgp // solidsnack // C1EBC57DC55144F35
Hi,
I usually just copy those .a files (that should be linked statically)
into `ghc --print-libdir`.
HTH Christian
Am 19.09.2012 13:06, schrieb Jason Dusek:
2011/12/1 Irene Knapp :
The typical trick to force GHC to statically link a C library
is to give the full path to the .a of it as one
2011/12/1 Irene Knapp :
> The typical trick to force GHC to statically link a C library
> is to give the full path to the .a of it as one of the object
> files in the GHC invocation that does the final linking. This
> means you don't need any -l or -L flags pertaining to that
> library. Some libr
Do you have some data that you'd like to understand better? I'm happy to
announce a new package called som that may help:
http://hackage.haskell.org/package/som
https://github.com/mhwombat/som/wiki (wiki)
A Kohonen Self-organising Map (SOM) maps input patterns onto a regular grid
(usually
I'm happy to announce a new major release of the grid package:
http://hackage.haskell.org/package/grid
https://github.com/mhwombat/grid/wiki (wiki)
WHAT'S NEW:
The GridMap module provides ordered maps from tiles on a grid to values. This
module is a wrapper around Grid and Map, in order
Hi.
> Oops, I hit send too prematurely, sorry for the seeming bluntness (but it is
> still a blunt message, can't apologize for that I suppose):
No need to apologize. There's a need for informal meetings as much (or
even more) as there is for courses and conferences.
> Perhaps a monthly informal
Hi list,
Oops, I hit send too prematurely, sorry for the seeming bluntness (but
it is still a blunt message, can't apologize for that I suppose):
On 19/09/12 09:14, Claude Heiland-Allen wrote:
On 19/09/12 08:52, Andres Löh wrote:
Registration for all these events is open. I hope to see many
> Is there an informal hangout without the £225 price-tag
Certainly a great idea. I guess there's most likely some informal
meeting after the Haskell eXchange. Perhaps Neil Mitchell knows if
there are any concrete plans yet? He's been putting together the
program for the conference.
Cheers,
And
On 19/09/12 08:52, Andres Löh wrote:
Registration for all these events is open. I hope to see many
of you there.
Is there an informal hangout without the £225 price-tag
Cheers,
Andres
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