han IxSet to store your points and
> still use happstack-state.
>
> - jeremy
>
> On Fri, Oct 1, 2010 at 1:53 PM, Thomas M. DuBuisson
> wrote:
> >> That is pretty close to how it would look using happstack-state. Here
> >> is a complete, runnable example which
> That is pretty close to how it would look using happstack-state. Here
> is a complete, runnable example which defines the types, a query,
> creates/initializes the database, performs the query, and prints the
> results.
[snip]
How is data stored in Happstack.State? I see the "Component" instanc
Vincent,
Due to spam-like comments on -cafe I hadn't been subscribed for a while
and missed your cryptohash discussion! Particularly:
> The main reason for this library is the lack of incremental api
exposed by
> current digest libraries, and filling the void about some missing
digest
> algorith
Comments on the zipWith' function inside of Data.ByteString say:
-- Rewrite rules
-- are used to automatically covert zipWith into zipWith' when a pack is
-- performed on the result of zipWith.
This is only true internally to Data.ByteString because the zipWith'
function could be inlined away by
> 1) Popularity statistics -- like debian's popcon, gives stats on how
> many people have which packages from hackage installed
Popularity has been suggested for some time. I think any new features
should be going into the happs version of Hackage
( http://code.haskell.org/hackage-server )
Thoug
Thomas van Noort wrote:
> However, I would like a single result for the complete list of
> properties instead of a result for each property. I realize that this
> restricts the properties to be of the same type, but that isn't a
> problem for my application.
You're types can be different, so lo
Magicloud wrote:
> Hi,
> As some articles say, do notation is expand to (>>) and (>>=)
> when
> being compiled.
> So I want to know the details. Like:
> main = do
> a <- getArgs
> b <- getLine
> myFunc1 (head a) b
> myFunc2 b (head a)
>
> I cannot figure out what is the (>>) a
On Fri, 2008-09-19 at 09:09 -0300, Marco Túlio Gontijo e Silva wrote:
> I added the NOINLINE annotations and even tried building with -fno-cse,
> but the result was the same. Do you have any other suggestions?
A while ago I made a shim using control-event to provide the
control-timeout api in Con
jason.dusek:
> What does Haskell have to say about cloud computing?
If by 'cloud computing' you wish to discuss mapReduce then:
http://www.cs.vu.nl/~ralf/MapReduce/paper.pdf
Map reduce in Haskell, enjoy!
Tom
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> What would theorem proofs do for me?
Imagine if you used SmallCheck to exhastively test the ENTIRE problem
space for a given property. Now imagine you used your brain to show the
programs correctness before the heat death of the universe...
Proofs are not features, nor are they code. What
> > Wow! 3x the performance for a simple change. Frustrating that there
> > isn't a protable/standard way to express this. Also frustrating that
> > the threaded version doesn't improve on the situation (utilization is
> > back at 50%).
GR, retraction, retraction!
I was obviously too tired
dons:
> Simon Marlow sez:
>
> The thread-ring benchmark needs careful scheduling to get a speedup
> on multiple CPUs. I was only able to get a speedup by explicitly
> locking half of the ring onto each CPU. You can do this using
> GHC.Conc.forkOnIO in GHC 6.8.x, and you'll also nee
Chris said:
> I personally think such pattern matching errors
> are a weaknesss of the language; with possibly no solutions to resolve.
Actually tools like CATCH [1] exist and could be incorporated into a
compiler to eliminate this problem.
[1] http://www-users.cs.york.ac.uk/~ndm/catch/
> Hmm thanks, that's interesting -- I was think it was probably caused
> by OS X, but it appears to happen on Linux too. Could you try running
> the old code too, and see if you experience the order of magnitude
> slowdown too?
The original program on my Linux 2.6.26 Core2 Duo:
[EMAIL PROT
> That's really interesting -- I just tried this.
>
> Compiling not using -threaded: 1.289 seconds
> Compiling using -threaded, but not running with -N2: 3.403 seconds
> Compiling using -threaded, and using -N2: 55.072 seconds
>
I was hoping to see a relative improvement when introducting an
op
wrt head [], Niels said:
> So now what? Action plan = []
Oh come now. Between ghci, hpc, and manual analysis I've never hit a
Haskell error and thrown my hands up, "I can't go any further, I'm at a
complete loss!" Also it helps that I run into this extremely rarely - I
have a larger habit of hid
You might be talking about my 'ipc' library [1] I mentioned here a
little while ago [2]. Don't forget the plethora of caviats (quick hack,
BSD sockets, trunkates messages around 4 kB).
I thought I'd be interested in developing and supporting some high level
IPC library but I'm really not and I do
> Do we have a formal convention for the naming of
> packages and/or the naming of the modules they contain?
There is a recommended set of categories and in general I believe
library authors try and follow the previously established names.
> How are name
> collisions supposed to be avoided?
In
I know someone else is going to say it, so I may as well beat them to
the punch:
Real World Haskell isn't released yet, but beta chapters are available
online at book.realworldhaskell.org/beta
As for me, I learned though the Yet Another Haskell tutorial, Haskell
School of Expression (book), Haske
> I have seen postings about work on message-passing IPCs for
> Haskell. I like STM but want to keep an open mind ... I can't find
> those postings. Can something remind of this work and where/how I can
> read about?
I made a quick hack composing BSD sockets from Network.Socket for higher le
> I could try GHC's new debugger. But my experiences with it so far have
> shown that for all but the most trivial programs possible, it becomes
> intractably difficult to figure out what the debugger is actually
> showing you.
GDB is to C as
(a) GHCi debugger :: Haskell
(b) Pigs :: Farmers
(
Cafe
I'm a bit lost on this exception and curious about what's going on. Is
there a valid reason for this exception that I am missing? Note the
hard-coded [0..100] could be any Word8 list you want (generated via
arbitrary, [], or other) and it gives the same result.
Load the module and perform:
Magicloud Magiclouds wrote:
> Say I have something like this in C:
> static int old;
> int diff (int now) { /* this would be called once a second */
> int ret = now - old;
> old = now;
> return ret;
> }
> Because there is no "variable" in Haskell. So how to do this in a
> FP way?
So
I think when Andy made HPC he added a way to mark code unreachable so it
wouldn't "harm" your test coverage report.
On Sat, 2008-06-14 at 19:58 +0100, Andrew Coppin wrote:
> I have a small idea. I'm curios if anybody else thinks it's a good idea...
>
> How about a {-# IMPOSSIBLE #-} pragma that
Cafe,
Daniel Larsson noticed a correctness issue with the pureMD5 package.
This issue would affect you if you built the value incrementally via the
'updateMD5' function (vs just using 'md5') and didn't provide 512 bit
long bytestrings (an MD5 block of operation).
As you can probably tell, I didn't
Why is there no mapAccumL' (strict)? Just a library deficiency that we
can remedy or am I missing something?
Don Stewart wrote:
> andrewcoppin:
> > OK, so this is a fairly basic question about list processing.
> >
> > Several times now, I have found myself wanting to process a list to
> > produ
2 at 00:19 -0400, Thomas M. DuBuisson wrote:
> Don,
> I'll throw future work ideas in the next releases cabal. The most
> obvious doors opened are Haskell rewrites of the current Xen
> infrastructure (virt-install, xm, xend). Slightly more interesting
> tasks could be (warning: r
Don,
I'll throw future work ideas in the next releases cabal. The most
obvious doors opened are Haskell rewrites of the current Xen
infrastructure (virt-install, xm, xend). Slightly more interesting
tasks could be (warning: random thoughts):
1) HAPPS server that can manage Xen domains (without r
All,
I'm just getting started with hsXenCtrl [1] as both a fun way to play
with Xen and become proficient with Haskell FFI. Once I get my
community.haskell.org account squared away I'll likely setup a public
darcs repo (and a homepage somewhere).
As for modules: I intend to expand on the trival F
Andrew,
What is "fast enough"? My informal understanding of the implementations
are:
1) Unoptimized [Word8] implementations (constant space, two or three
orders of magnatude slower than C)
2) Bindings to 'C' routines (typically O(n) space due to strict
ByteStrings and no split out of initialConte
Andrew,
I spent a reasonable amount of time making pureMD5 (available on
hackage) faster, which mainly ment strictness annoitations and unboxing
strict fields, but I also spent a good deal of time with the profiler.
One of my early versions was fairly slow due to the converting of the
LPS to blocks
Id is an operation over types yielding a type, as such it doesn't make
much sense to me to have (Id a -> Id a) but rather something like (a ->
Id a). One could make this compile by adding the obvious instance:
> type instance Id a = a
Curiously, is this a reduction from a real world use of famil
I minor changes, fixing up my chunking function (finally) thus
eliminating the space leak. Performance is now under 3x that of C!
Yay! Also, nano MD5 benched at 1.15x 'C' (for files small enough for
strict ByteStrings to do ok).
Get the code:
darcs get http://code.haskell.org/~tommd/pureMD5
On
Glad you asked!
http://sequence.complete.org/node/367
I just posted that last night! Once I get a a community.haskell.org
login I will put the code on darcs.
The short of it it:
1) The code is still ugly, I haven't been modivated to clean.
2) Manually unrolled, it is ~ 6 times slower than C
3)
All,
I've been casually developing a PacketBB (i.e. Generalized Manet Packet
Format) library in Haskell. I think I have a need to pass state
information as a phantom type - I'll step through the issue now.
With the 'AddressBlock' (S5.2.1 packetBB draft 8), network addresses are
abbreviated as se
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