On Mon, Nov 3, 2008 at 7:55 PM, minh thu [EMAIL PROTECTED] wrote:
Well, it seems you can't really write
(fromJust . fromDynamic) someDynamic
without giving the type of what you expect.
Well not by itself. But context will usually determine the type. For example:
putStrLn . fromJust .
2008/11/4, [EMAIL PROTECTED] [EMAIL PROTECTED]:
minh thu asked a tricky question, about writing
extract :: Typeable a = TypeRep - Dynamic - a
The question here is what determines the type 'a'. One answer is that
'a' is determined from the context, e.g.,
(extract tr dyn) + 1.0
fixes
Achim Schneider barsoap at web.de writes:
That's about what I meant with a screenshot. Linking a copy of the html
generated for e.g. the Prelude would greatly help people who are just
browsing Hackage and are trying to figure out what your package is all
about.
Well, I can't do the
Hello Nun,
Monday, November 3, 2008, 11:53:08 PM, you wrote:
2) the Win32 package in this link gives a type error during the
setup build phase (expecting exception and given ioerror?) but you
can compile the example against the Win32 package in ghc 6.8.3
of course - it's written against
On Thu, Jul 31, 2008 at 6:37 PM, Don Stewart [EMAIL PROTECTED] wrote:
agentzh:
On Thu, Jul 31, 2008 at 1:56 AM, Don Stewart [EMAIL PROTECTED] wrote:
We've had no problems with this and apache at least. Is lighttpd
doing something funny with error logging?
It seems that Apache is doing
Hello Maurício,
Tuesday, November 4, 2008, 3:47:17 PM, you wrote:
Haskell syntax allows a comma at the end of names
to be imported or exported, like in the second
line. What does that mean?
it simplifies editiing of lists: you can add/remove lines without
changing surrounding ones:
import
Maurcio [EMAIL PROTECTED] wrote:
About this teste code:
module Main (main) where {
import Foreign hiding (unsafePerformIO,Foreign.Ptr,Data.Bits,) ;
blo = xor 10 10 :: Int ;
main = return ()
}
You're only hiding the typeclass Data.Bits, not the function xor. To do
that, you have to
About this teste code:
module Main (main) where {
import Foreign hiding (unsafePerformIO,Foreign.Ptr,Data.Bits,) ;
blo = xor 10 10 :: Int ;
main = return ()
}
You're only hiding the typeclass Data.Bits, not
the function xor. To do that, you have to write
import Foreign hiding
Dear Haskellers,
I've just uploaded a few packages to Hackage which I have produced
while working at Anygma. I thought that people might be interested in
knowing about these:
obj-0.1:
A library for loading and writing obj 3D models. This is still an
early version and rather limited,
Hello all,
For my mud client Yogurt (see hackage) I'm currently working on
improving the efficiency of the hooks. Right now several hooks, each
consisting of a regex and an action can be active at the same time.
Every time a line of input is available (usually several times a second)
I run the
Martijn van Steenbergen [EMAIL PROTECTED] wrote:
Does anyone have any experience with this? What's the best way to
achieve this?
For anything remotely connected to parsing, always use parsec.
I'd not be surprised if the beast is touring complete in itself... or
can parse something that can
On Tue, 2008-11-04 at 18:26 +0100, Achim Schneider wrote:
Martijn van Steenbergen [EMAIL PROTECTED] wrote:
Does anyone have any experience with this? What's the best way to
achieve this?
For anything remotely connected to parsing, always use parsec.
I'd not be surprised if the beast
Hi Martijn,
It's not that tricky if you do a regular expression state machine yourself, but
that's probably a bit too much work. One way to get a speed up might be to take
the regular expressions a,b,c,d and generate a regex a+b+c+d, and one a+b. You
can then check any string s against
On Tue, Nov 4, 2008 at 9:26 AM, Achim Schneider [EMAIL PROTECTED] wrote:
Martijn van Steenbergen [EMAIL PROTECTED] wrote:
For anything remotely connected to parsing, always use parsec.
I'd not be surprised if the beast is touring complete in itself...
Actually, this can count against you.
On Mon, Nov 3, 2008 at 3:45 PM, Svein Ove Aas [EMAIL PROTECTED] wrote:
On Mon, Nov 3, 2008 at 11:31 AM, Tobias Bexelius
[EMAIL PROTECTED] wrote:
Before Direct3D 10, its too costly to read back the updated vertex data
in every frame, which force you to make this kind of operations on the
David Menendez-2 wrote:
On Mon, 3 Nov 2008, Luke Palmer wrote:
I was actually being an annoying purist. f is strict means f _|_ =
_|_, so strictness is a semantic idea, not an operational one.
I think Luke was commenting on the terminology, not the optimization.
We have a tendency to
Sorry for referring to a post, a bit ago.
http://www-users.cs.york.ac.uk/~ndm/derive/ (Deriving Generic Functions
by Example).
Thanks for the pointer, it was already on my to-read-pile :-)
I think using Template Haskell for your work would fit very nicely, so
is a good choice to learn :-)
Dan Piponi [EMAIL PROTECTED] wrote:
On Tue, Nov 4, 2008 at 9:26 AM, Achim Schneider [EMAIL PROTECTED]
wrote:
Martijn van Steenbergen [EMAIL PROTECTED] wrote:
For anything remotely connected to parsing, always use parsec.
I'd not be surprised if the beast is touring complete in itself...
wren ng thornton wren at freegeek.org writes:
[snick]
isum 0 s = s
isum n s = isum (n-1) (s+n)
This is tail recursive, and will be optimized to an iterative loop;
[snick]
In terms of having a compiler 'smart enough', it's not clear that
functions of this sort ought to be inferred
Patai Gergely [EMAIL PROTECTED] writes:
My only problem is that if I try to write a program without
thinking about performance first and not bothering with annotations as
long as it works, I end up with something that's practically
impossible to profile as the costs spread everywhere.
I
I think using Template Haskell for your work would fit very
nicely, so
is a good choice to learn :-)
I already got used to TH a bit, but I am not sure if it is
appropriate for my purpose, or at least not completely.
I want to load Haskell code into my program at runtime in an
Thanks everyone for the answers. I understood the underlying mechanism,
and I did see that turning on optimisation helps, as I said in the
comments. I just wasn't aware that this analysis is not turned on by
default, my bad for not reading the FM.
So the final verdict is that type and strictness
The regex-tdfa package (and regex-posix) implement subexpressions capture.
So if you want to match alpha beta and gamma in parallel you could write
(alpha)|(beta)|(gamma) and check which subexpression has the non-empty match.
This becomes slightly complicated if there are parenthesis and
On Tue, Nov 04, 2008 at 08:34:37PM +0100, Achim Schneider wrote:
Parsec is a thousand times more efficient for such things than regular
expressions, and you can just lazily parse all the input into a list
of data constructors and happily fold it into your state...
I would recommend you to
On Thu, Oct 30, 2008 at 11:53 AM, Daniil Elovkov
[EMAIL PROTECTED] wrote:
Yes, HSQL supports Oracle natively, through OCI. hsql-oracle isn't on
hackage, only in the repository.
That's exactly what I was looking for, but for HDBC instead. Since OCI
bindings for HDBC don't seem to exist, I guess
On Tue, Nov 4, 2008 at 9:05 AM, Martijn van Steenbergen
[EMAIL PROTECTED] wrote:
For my mud client Yogurt (see hackage) I'm currently working on
improving the efficiency of the hooks. Right now several hooks, each
consisting of a regex and an action can be active at the same time.
Every time
Hi,
About this teste code:
module Main (main) where {
import Foreign hiding (unsafePerformIO,Foreign.Ptr,Data.Bits,) ;
blo = xor 10 10 :: Int ;
main = return ()
}
Data.Bits is in the 'hiding' list. According to
the syntax reference, this seems not to be allowed.
GHC allows it, but do allow
John,
On Thu, Oct 30, 2008 at 2:48 PM, John Goerzen [EMAIL PROTECTED] wrote:
I would certainly happily reference anyone's native Oracle HDBC
backend too, though!
You may want to reference mine, given that there aren't any others
currently. Just be aware that it really isn't ready for mass
Are there cases (function or list) where the result of foldl (or foldr)would
be different that foldl' (or foldr')?
thanks,
daryoush
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Daryoush Mehrtash [EMAIL PROTECTED] wrote:
Are there cases (function or list) where the result of foldl (or
foldr)would be different that foldl' (or foldr')?
Yes, in two cases folds can differ:
a) You've got an infinite list, in which case you don't want to go to
the end of it before
On Tue, 2008-11-04 at 15:08 -0800, Daryoush Mehrtash wrote:
Are there cases (function or list) where the result of foldl (or
foldr)would be different that foldl' (or foldr')?
There is no foldr'. And yes, foldl and foldl' are different functions
and thus return different results on some
Am Mittwoch, 5. November 2008 00:08 schrieb Daryoush Mehrtash:
Are there cases (function or list) where the result of foldl (or
foldr)would be different that foldl' (or foldr')?
thanks,
daryoush
Simple example:
import Data.List
weird :: Int - Int - Int
weird _ 0 = 0
weird x y = x*y
list
On Tue, 2008-11-04 at 10:02 -0800, Dan Piponi wrote:
On Tue, Nov 4, 2008 at 9:26 AM, Achim Schneider [EMAIL PROTECTED] wrote:
Martijn van Steenbergen [EMAIL PROTECTED] wrote:
For anything remotely connected to parsing, always use parsec.
I'd not be surprised if the beast is touring
On Tue, 2008-11-04 at 12:18 +0100, Patai Gergely wrote:
Thanks everyone for the answers. I understood the underlying mechanism,
and I did see that turning on optimisation helps, as I said in the
comments. I just wasn't aware that this analysis is not turned on by
default, my bad for not
2008/11/5 Daryoush Mehrtash [EMAIL PROTECTED]:
Are there cases (function or list) where the result of foldl (or foldr)would
be different that foldl' (or foldr')?
Maybe this wiki article I wrote some time ago will answer your question:
http://haskell.org/haskellwiki/Foldr_Foldl_Foldl'
regards,
On Wed, Nov 5, 2008 at 12:43 AM, Bas van Dijk [EMAIL PROTECTED] wrote:
2008/11/5 Daryoush Mehrtash [EMAIL PROTECTED]:
Are there cases (function or list) where the result of foldl (or foldr)would
be different that foldl' (or foldr')?
Maybe this wiki article I wrote some time ago will answer
Nonsense, isum is strict in s. If s is bottom, isum will always return bottom.
This is the definition of being strict.
-- Lennart
On Mon, Nov 3, 2008 at 10:35 PM, Don Stewart [EMAIL PROTECTED] wrote:
frantisek.kocun:
yet I need to add a $! to the recursive call of isum to get a truly
Informally, a pure program an executable such that the
stream of bytes entering it totally determines the stream of
bytes leaving it.
Many useful programs that I would like to write in Haskell
don't fall into this category -- for example, network servers
-- but a lot of their
You're essentially describing functional reactive programming. You end
up with the system being described as pure, reactive values and
plugging IO based streams in at the edges.
Have a look at the wiki description
(http://www.haskell.org/haskellwiki/Functional_Reactive_Programming)
and especially
On 2008 Nov 4, at 19:12, Jason Dusek wrote:
Many useful programs that I would like to write in Haskell
don't fall into this category -- for example, network servers
-- but a lot of their components do. Can these components can
be Haskell functions without IO in their signatures?
I'm
Hello all,
I'm working through the practical HXT examples and have gotten stumped
with the weather example[1]. I'm using GHC 6.8.3 and HXT 8.1.0. I
compile the example like so...
[EMAIL PROTECTED]:~
$ ghc --make weather.hs
[1 of 1] Compiling Main ( weather.hs, weather.o )
Linking
Oh my, how silly of me. The page has moved to
http://www.weather.gov/xml/current_obs/KAGC.xml ! Firefox simply
follows the redirect.
Thanks for the putStrLn suggestion, George.
On Tue, Nov 4, 2008 at 5:28 PM, George Pollard [EMAIL PROTECTED] wrote:
On Tue, 2008-11-04 at 17:04 -0800, Brian
G'day all.
Quoting Achim Schneider [EMAIL PROTECTED]:
Considering that he's talking about a mud, I figure the grammar is a
quite straightforward
command = l[eft] | r[ight] | ... | t[ake] item | c[ast] spell
That is, I'd be very surprised if you even need more than two or three
characters
G'day all.
Quoting Achim Schneider [EMAIL PROTECTED]:
Considering that he's talking about a mud, I figure the grammar is a
quite straightforward
command = l[eft] | r[ight] | ... | t[ake] item | c[ast] spell
That is, I'd be very surprised if you even need more than two or three
characters
T Willingham t.r.willingham at gmail.com writes:
I am thinking of our troglodytic friend 'make', which will run (for
example) 4 parallel jobs when given the option make -j4. Even
'rake', the ruby version of make, now has a branch (called drake)
which does the parallel -j option.
From the
let has [] = False; has _ = True
-- this one is ok
let empty list = case has list of True - False; False - True
-- the following is problematic
let emp (has - True) = False; emp (has - False) = True
interactive:1:4:
Warning: Pattern match(es) are overlapped
In the definition of
Hello Jason,
Wednesday, November 5, 2008, 3:12:29 AM, you wrote:
Many useful programs that I would like to write in Haskell
don't fall into this category -- for example, network servers
-- but a lot of their components do. Can these components can
be Haskell functions without IO in
Hello Chad,
Wednesday, November 5, 2008, 6:34:01 AM, you wrote:
ghc --make -j4 Foo.hs
afair, it was implemented and not shown speed improvements. ask Simon
--
Best regards,
Bulatmailto:[EMAIL PROTECTED]
___
Hello Cetin,
Wednesday, November 5, 2008, 8:34:14 AM, you wrote:
let emp (has - True) = False; emp (has - False) = True
Warning: Pattern match(es) are overlapped
proibably it's because GHC can't check view patterns for overlaps?
--
Best regards,
Bulat
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