2009/1/6 Luke Palmer lrpal...@gmail.com:
2009/1/6 Wang, Chunye (NSN - CN/Beijing) chunye.w...@nsn.com
Dear haskeller,
Can I destructive rebind a local variable like this
import System.Directory
test filename = do
is_dir - doesDirectoryExist filename
let filename = if not is_dir
Hi Evan,
You can also reuse the name exactly by using bind+return instead of
let:
test filename = do
is_dir - doesDirectoryExist filename
filename - return $ if not is_dir then filename else filename
I'm not a huge fan of the prime thing because it's tiny and easy to
miss and if you
Dan Weston wrote:
For the 2D grid zipper above, moving around is O(1) but update is O(log
n). This is acceptable; also because I'm quite confident that a zipper
for a 2D grid with everything O(1) does not exist. I can prove that for
a special case and should probably write it down at some
Daniil Elovkov wrote:
Ok, enough talking to myself :)
If anybody ever wants to build hsql-mysql on windows and has the same
problems as I had, here's how it should be done.
The problem I had seemed to be that libmysql.dll uses stdcall, but
names its functions without @n decoration. Thus, when
The issue here is not whether or not the code is pretty or elegant, but
whether or not I get correct execution of what I have, which is a correct
statement of what I want (even if not the prettiest or most lint free),
and I don't. There are lots of ways to work around the problem, but that
Exactly. The best you can do is try to reduce your code to a tiny
fragment that still exposes the problem, and report it as a bug.
On Tue, Jan 6, 2009 at 4:52 PM, Murray Gross mgros...@verizon.net wrote:
The issue here is not whether or not the code is pretty or elegant, but
whether or not I
Hi Murray,
The issue here is not whether or not the code is pretty or elegant, but
whether or not I get correct execution of what I have, which is a correct
statement of what I want (even if not the prettiest or most lint free), and
I don't.
Sorry, I was merely responding to someone else
Bulat Ziganshin wrote:
Hello Günther,
Monday, December 22, 2008, 1:57:22 AM, you wrote:
try -threaded, +RTS -N2, and forkOS simultaneously. it may work - i
don't see reasons why other threads should be freezd why one does
unsafe call
Please don't suggest using forkOS - it will probably harm
John Goerzen wrote:
Duncan Coutts wrote:
On Mon, 2008-12-22 at 10:30 +, Malcolm Wallace wrote:
The terminology seems counter-intuitive, but in other other words, a
safe call is slower but more flexible, an unsafe call is fast and
dangerous. Therefore it is always OK to convert an unsafe
Duncan Coutts wrote:
On Tue, 2008-12-23 at 03:56 +0100, wman wrote:
Thanks to you all for inspiration.
My web app (which otherwise ran ok) was getting stuck while getting
harassed by ab (apache-benchmark) after receiving some 800+ requests
in short succession (not less, never gotten to 900,
My last note had an error in it, and the code originally sent to the list
should be ignored. I have attached the current version of the code, and
here is some further information (the behavior is different, by the way,
but still apparently wrong).
I have attached the current version of the
Alright... I *think* I'm nearly there, but I can't figure out how to
derive a class instance using record accessors and updaters... Can
anyone help? There are [| XXXf |] instances at the end of the module
and they all need replaced, but I can't figure out what to replace
them with. The basic
Hi,
has anybody here successfully tried to attach another database to an
Sqlite database with HDBC-Sqlite3?
I keep failing, so I'd be grateful for a hint how to do it.
Günther
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Haskell-Cafe@haskell.org
Here is a program which illustrates an unexpected behaviour:
import Graphics.PDF
main = runPdf bug.pdf standardDocInfo (PDFRect 0 0 100 100) pdf
where
pdf = do
p - addPage Nothing
drawWithPage p $ drawText $
sequence $ replicate 10 $
Roman,
The text monad is very low level and its functions are mapping
directly to the PDF text environment commands.
text function is generating two PDF commands : Td and Tj. In Adobe
PDF spec :
Td : Move to the start of the next line, offset from the start of the
current line by (tx ,
If you believe this is a compiler bug, please report it:
http://hackage.haskell.org/trac/ghc/newticket?type=bug
mgross21:
My last note had an error in it, and the code originally sent to the list
should be ignored. I have attached the current version of the code, and
here is some
ekirpichov:
Hi,
I'm parsing Java classfiles with Data.Binary, the code is here:
http://paste.org/index.php?id=4625
The problem is that the resulting code parses rt.jar from JDK6 (about
15K classes, 47Mb zipped) in 15 seconds (run the program with main
-mclose rt.jar, for instance), which
Am Dienstag, 6. Januar 2009 18:32 schrieb Murray Gross:
My last note had an error in it, and the code originally sent to the list
should be ignored. I have attached the current version of the code, and
here is some further information (the behavior is different, by the way,
but still
On Sat, Jan 3, 2009 at 4:06 PM, Massimiliano Gubinelli
m.gubine...@gmail.com wrote:
I've tried to undestand the paper, in particular the relation between
the combinators written in cps style and combinators written using a
Maybe type (i.e pattern matching functions returning Maybe to signal
Thanks; I'm using GHC 6.10.1 and the latest binary now, and things get
inlined perfectly well.
Anyways, the main bottleneck turned out to be the performance of
zip-archive , which is now (since 1-2 days ago) ~25x better, and now
the Haskell version is about just 2.5x slower than the Java one, and
Apfelmus,
Thanks for the reply.
From your description (without reading the code ;))
I hope the code is better than my description! :) The structure is more like
Nothing(RK 0 _)
Nothing(RK 1 _)
A(RK 2 4)
B(RK 3 6)
C(RK 2 0)
The root of the tree is the center and you can
Hi,
I've written a circularly linked list, but there is some code in it I feel
is redundant, but don't know how to get rid of:
-- Transactional loop. A loop is a circular link list.
data Loop a
= ItemLink
{ item :: a
, prev :: TVar (Loop a)
, next :: TVar (Loop a)
}
Hi.
Here:
http://damienkatz.net/2008/03/what_sucks_abou.html
I found how Erlang (or at least old versions of Erlang) handles out of
memory failure: it just calls exit(1).
How is this handled in GHC?
- exit(1)?
- abort()?
- IO exception?
Thanks Manlio Perillo
On 6 jan 2009, at 18:08, Jeff Heard wrote:
Alright... I *think* I'm nearly there, but I can't figure out how to
derive a class instance using record accessors and updaters... Can
anyone help? There are [| XXXf |] instances at the end of the module
and they all need replaced, but I can't
manlio_perillo:
Hi.
Here:
http://damienkatz.net/2008/03/what_sucks_abou.html
I found how Erlang (or at least old versions of Erlang) handles out of
memory failure: it just calls exit(1).
How is this handled in GHC?
- exit(1)?
- abort()?
- IO exception?
GHC:
$ ./A +RTS
Manlio Perillo ha scritto:
[...]
How is this handled in GHC?
- exit(1)?
- abort()?
- IO exception?
Ok, found it by myself:
http://hackage.haskell.org/trac/ghc/ticket/1791
It is also explicitly documented in:
http://haskell.org/ghc/docs/latest/html/libraries/base/Control-Exception.html
and
Jeff Heard schrieb:
Alright... I *think* I'm nearly there, but I can't figure out how to
derive a class instance using record accessors and updaters...
Has this something to do with
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/data-accessor-template
?
You can use undefined or error ... :
{-# LANGUAGE RecursiveDo #-}
import Control.Concurrent.STM
import Control.Monad.Fix
-- Transactional loop. A loop is a circular link list.
data Loop a
= ItemLink
{ item :: a
, prev :: TVar (Loop a)
, next :: TVar (Loop a)
}
--
On Tue, 6 Jan 2009, Daniel Fischer wrote:
Could you elaborate? I couldn't find an inconsistency using your previous
code, it behaved as it should (until I ^C-ed it).
In several versions of the code, now unfortunately lost because of a crash
on a power failure (which is extremely rare
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